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1999
Photovoltaics
Special Research
Centre
UUNNSSWW
1999
Photovoltaics
Special Research
Centre
The University of New South Wales
Centre for Photovoltaic Engineering
Electrical Engineering Building
The University of New South Wales
UNSW SYDNEY NSW 2052
AUSTRALIA
Tel+61 2 9385 4018 Fax+61 2 9662 4240
E-mail: [email protected] http://www.pv.unsw.edu.au
Annual Report
UUNNSSWW
� ii iii �
ContentsThe 1999 Annual Report contains three sections which are colour coded as follows:
Red: Photovoltaics Special Research Centre End-of-Grant Report . . . . . . . . . . . . . . . . . . . . . .S1
Orange: Photovoltaics Special Research Centre1999 Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PV1
Green: Special Research Centre for Third Generation PhotovoltaicsStart-Up Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T1
� iv v �
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE
area of science and technology pro-
moting human welfare. They were
the first all-Australian team to win
the award since 1992.
Best Paper Awards,SapporoFollowing on from the best paper
award it received at the 2nd World
Conference on Photovoltaic Solar
Energy Conference in Vienna in
1998, the Centre also fared well at
the next major international confer-
ence in the field, the 11th
International Photovoltaic Science
and Engineering Conference in
Sapporo, Japan in September, 1999.
A best paper award was presented
to Jianhua Zhao, Aihua Wang and
Martin Green for their paper on
high efficiency solar cells. Their
work involving international collab-
oration in exploring the effect of
different silicon preparation meth-
ods also won a special award, jointly
with the Fraunhofer Institute for
Solar Energy Systems, Germany
and Tokyo University of Agri-
culture and Technology, Japan.
New Centre forAdvanced CellsWith the 9-year grant period for the
Photovoltaics Special Research
Centre finishing at the end of 1999,
the group was successful in obtain-
ing support for a new ARC Special
Research Centre in Third Gen-
eration Photovoltaics which com-
menced in January, 2000. This
Centre will have a more restricted
scope than the Photovoltaics Special
Research Centre, seeking to develop
a new generation of thin-film cell of
efficiency much closer to the limit-
ing performance possible for the
conversion of sunlight to electricity
(93%). More details are contained in
this Centre's start-up report at the
rear of this volume.
Pacific Solar Trial MarketingCentre spin-off, Pacific Solar,
entered a new phase of develop-
ment with the trial marketing of
residential photovoltaic systems in
the Sydney area. The new systems
featured a new mounting structure
developed by Pacific Solar.
Although presently using imported
module-level inverters and solar
laminates, the company plans to
include its own inverter into such
systems in 2000 and the Centre's
silicon-on-glass thin-film technolo-
gy in 2003. Two other licensees, BP
Solar and Solarex, announced the
formation of the combined BP
Solarex during the year, now clearly
the world's largest photovoltaic
manufacturer.
1999 Australia Prize In February, Centre Directors
Martin Green and Stuart Wenham
were presented with the Australia
Prize by Prime Minister John
Howard in a special ceremony in
Parliament House in Canberra. The
Prize is an international award for
specific achievement in a selected
PERL CELL.
Silicon Cell World Records
Two new world records for silicon solar cell performance
were established by the Centre during 1999. A new out-
right record of 24.7% energy conversion efficiency was
demonstrated together with a new record of 24.5% for a
cell made on a substrate other than one prepared by the
float-zone process.
New Directors To take up the Directorship of thenew Centre for Third GenerationPhotovoltaics, Professor MartinGreen resigned from the Director-ship of the Photovoltaics SpecialResearch Centre at the end of 1999.The new Directors are Dr JianhuaZhao, Dr Christiana Honsberg, andDr Armin Aberle with responsibili-ties for the areas indicated on theaccompanying photographs.
PACIFIC SOLAR ROOFTOP.
DR ARMIN ABERLE
DIRECTOR (THIN FILM)
Aurora 101 Wins World Solar Challenge
Using high performance solar cells manufactured by the
Centre, the Australian solar car, Aurora 101, won the
1999 World Solar Challenge, the major international
solar car race along the 3,000 kilometer course from
Darwin to Adelaide. This follows the Centre's success in
the previous event in 1996, where the Honda Dream
won convincingly using Centre cells. Early in the race's
history, the Spirit of Biel also won using cells made
under license to the Centre, giving the Centre 3 wins
from the 5 races so far.
1 9 9 9 H I G H L I G H T S
1999 Highlights1999 Highlights
PROFESSOR MARTIN GREEN (LEFT), THE PRIME MINISTER,
JOHN HOWARD AND PROFESSOR STUART WENHAM.
DR JIANHUA ZHAO
DIRECTOR (HIGH EFFICIENCY)
DR CHRISTIANA HONSBERG
DIRECTOR (BURIED CONTACT)
vii �� vi
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE D I R E C T O R ’ S R E P O R T
The final year of operation
continued the success of ear-
lier years with notable
achievements in both “first-
generation” silicon wafer-
based research and in “sec-
ond-generation” thin-film
solar cell development. As
detailed in the end-of-grant
report that follows, the
Centre surpassed its original
two aims relating to both
these generations of solar cell
technology. It also comfort-
ably exceeded its third aim of
stimulating research activities
in the photovoltaic systems
and applications area.
Highlights during the grant peri-
od have been the on-going
improvements in “first-genera-
tion” silicon solar cell efficien-
cy, with a further improve-
ment to a record 24.7% effi-
ciency posted during 1999.
BP Solarex also successful-
ly commercialised the
Centre’s “buried contact”
cells during the grant
period, with these
becoming the cells pro-
duced in the highest
volume in Europe over
recent years.
The highlight in the
area of “second-gen-
eration” thin-film technol-
ogy has been the establish-
Australia across all disci-
plines. This Centre has activ-
ities clearly differentiated
from the Photovoltaics
Special Research Centre and
the Key Centre for Photo-
voltaic Engineering, concen-
trating on a “third-genera-
tion” of photovoltaic tech-
nology, not yet fully con-
ceived, let alone implement-
ed. I will be the Director of
this new Centre with Dr
Armin Aberle, Deputy
Director. Dr Aberle will have
special responsibilities for
the new Centre’s experimen-
tal programs.
The new Centre will attempt
to develop ideas, able to be
implemented in thin-film
form, likely to significantly,
rather than incrementally,
improve photovoltaic cell
performance beyond that of
a single junction device.
Tandem stacks of solar cells
and Dr Armin Aberle as the
new Directors. These would
be responsible for continuing
the High Efficiency, Buried
Contact and Silicon Thin-Film
strands of the original Centre,
respectively. Each of these
areas is at, or close to, the
forefront of international
activity in these areas. Funding
for these activities will be
sought through a variety of
sources, including competitive
grants schemes.
May I take this opportunity to
thank those who have con-
tributed to the past success of
the Photovoltaics Special
Research Centre. We are enter-
ing an exciting period for pho-
tovoltaics. I hope we will be
able to build on past successes,
to help accelerate the wide-
spread adoption of this new,
benign and sustainable energy
generation technology.
of differing bandgaps are
probably the best known
example of such a third-gen-
eration approach, whereby
efficiency can be increased
merely by serially stacking
more cells. The new Centre
will explore approaches capa-
ble of similar efficiency but
using more innovative “paral-
lelled” approaches. More
information on the new
Centre and some of the ideas
it intends to explore can be
found in the “start-up”
report at the rear of the pres-
ent publication.
Finally, although I have re-
signed as its Director, an on-
going role for the original
Photovoltaics Special Re-
search Centre has been
approved. Approval has been
gained for the continuation of
the Centre and its world-lead-
ing research with Dr Jianhua
Zhao, Dr Christiana Honsberg
ment of Pacific Solar Pty Ltd,
specifically to commercialise
the Centre’s work in this area.
This initiative forms the basis
of one of the largest invest-
ments in renewable energy in
Australian history, as well as
one of the largest industry-
university commercialisation
projects.
Perhaps the greatest success in
the systems area relates to the
photovoltaic project for the
athletes’ village for the Sydney
2000 Olympics. This has been
assessed as the major environ-
mental success of these
“Green Olympics”. Many of
the parties involved in this
project gained their initial
experience with photovoltaics
via contact with the Centre, in
addition to the direct role
played by the Centre in its con-
ception and implementation.
Undoubtedly aided by the
achievements of the Photo-
voltaics Special Research
Centre, the University was
successful in its application
for a similar ARC Special
Research Centre in Third
Generation Photovoltaics.
The Centre, which com-
menced in January, 2000, is
one of a small number of
such Centres selected from
applications from around
Director’s Report
PROFESSOR MARTIN GREEN,FOUNDING DIRECTOR,PHOTOVOLTAICS SPECIAL RESEARCH CENTRE
At the end of 1999, the Photovoltaics Special Research
Centre completed the maximum 9-year period of support
from the Australian Research Council.
� Sviii
Photovoltaics Special
Research Centre
End-of-Grant Report
Photovoltaics Special
Research Centre
End-of-Grant Report
T A B L E O F C O N T E N T S
S3 �
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S4
Aims and Outcomes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S8
Device Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S12
Supporting Fundamental Work . . . . . . . . . . . . . . . . . . . . . . . . . . . .S18
Systems Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S20
Education, Training and Technology Transfer . . . . . . . . . . . . . . . .S21
External Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S22
Financials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S23
Publications (1991 -1999) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S24
Table of ContentsTable of Contents
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT S U M M A R Y
S5 �� S4
The Photovoltaics Special Re-
search Centre was established in
1991 with support from the
Australian Research Council
(ARC) Research Centres Sch-
eme. At this time, it was one of
a small number of Centres
selected from all disciplines
around Australia after extensive
review. The Centre was initially
funded for a period of 6 years,
subject to review during 1993.
The Centre was reviewed again
in 1996 with the result that the
period of ARC funding was
extended to the end of 1999,
completing the maximum 9 year
period for Special Research
Centre funding. ARC funding
was approximately AU$1 mil-
lion/year (US$600,000/year)
over this period, although this
was supplemented by income
from other sources. The ARC
funds accounted for approxi-
mately 40% of the funds avail-
able for Centre related activities.
The original aims of the Centre
were maintained over its 9 year
funding period. The three origi-
nal aims were:
� To maintain and extend
Australia’s lead with convention-
al silicon solar cells and develop
these cells to their full potential;
� To develop silicon “thin film”
technology based on depositing sil-
icon onto glass and to be involved
with one or more commercial col-
laborators with associated technol-
ogy transfer by 1996;
� To develop a co-ordinated set of
activities in the photovoltaics sys-
tem area, with these to be funded
largely from other sources.
The original aims have been
fully met and, in some cases,
substantially exceeded. The
Centre has maintained a clear
advantage with conventional or
“first generation” silicon cell
performance over its life. With
the confirmation of 24.7% cell
efficiency during 1999, the
advantage over the next best
result internationally has been
extended to over 5% (relative),
compared to a more modest 3%
advantage when the Centre
commenced, despite significant
overall improvements during
this period. Another notable
result was the demonstration of
19.8% efficiency on a multicrys-
talline silicon wafer during 1998,
establishing an even greater
margin over the next best result
internationally in this area.
Apart from these performance
advantages, other achievements
in work related to the first of
the above aims are noteworthy.
These include the successful
commercialisation of the Uni-
The third aim has also been
comfortably exceeded with the
diversion of only a small frac-
tion of the ARC grant as seed-
ing funds for this purpose. The
University is now widely recog-
nised for its photovoltaic sys-
tems activities, receiving major
support from Pacific Power,
EnergyAustralia, Australian aid
agencies and the Australian Co-
operative Research Centre for
Renewable Energy (ACRE) for
this work over the grant period.
Highlights include the installa-
tion of the first grid-connected
photovoltaic systems in New
South Wales at the University's
Solar Research Facility at Little
Bay, the establishment of a
Design Assistance Division to
provide advice, not otherwise
readily available, to prospective
users of photovoltaic systems;
the development and running of
accreditation courses for the
Solar Industries Association of
Australia; acting as a focus for
the development of standards
for inverters for grid-connected
photovoltaic systems; working
with various parties in connec-
tion with providing photovoltaic
power to each of the more than
600 homes comprising the
Athletes’ Village for the Sydney
2000 Olympics; and the running
of a variety of courses including
the first international internet
courses on photovoltaic devices
and systems. Independent con-
firmation of the quality of this
systems work comes from a best
paper award, “Best in Terrestrial
Applications Area” at the 1st
World Conference on Photo-
voltaic Energy Conversion in
Hawaii in December, 1994, an
invited plenary session paper for
system researcher, Dr Muriel
Watt, at the 26th IEEE Photo-
of 34 postgraduate research the-
ses were successfully completed
by Centre students, with 22 of
these at the doctoral level. The
Centre has published several
textbooks on photovoltaics that
are the most widely used in this
field, internationally, amongst
other achievements in the aca-
demic area. A summary of
notable outcomes is given in
Table S1.
voltaic Specialists Conference in
Washington in May, 1996, the
most highly rated systems paper
in the international journal
“Progress in Photovoltaics”
over the 1993-1995 period, and
several best paper awards in this
area at local conferences.
The Centre has also had notable
success in other areas not direct-
ly related to the three specific
aims above. For example, a total
versity’s buried contact technol-
ogy by BP Solarex during the
grant period. This has now
become the most successfully
commercialised new solar cell
technology over this period.
Similar success has been enjoyed
in commercialising other Centre
“first generation” cell technolo-
gy for use on spacecraft. A relat-
ed result has been the success
enjoyed by Centre cells in solar
car racing, with Centre cells on
the winning car in three of the
four major international solar
car races held during the
Centre’s life.
Achievement of the second aim
relating to the development of a
“second generation” of silicon
thin-film technology may prove
even more important to the
photovoltaics field in the long
term. In 1994, the Centre
announced the filing of patent
applications on a new cell struc-
ture suitable for use on low
quality, silicon thin-films, such
as could be deposited onto glass.
This attracted international
media coverage and was hailed
as a “conceptual breakthrough”
at the time. The new develop-
ment stimulated the largest
investment to date in renewable
energy technology in Australian
history, by local utility, Pacific
Power, to evaluate the commer-
cial potential of this approach.
A new company, Pacific Solar,
was formed in 1995 to perform
this evaluation. The company
successfully commenced pilot-
production of silicon-on-glass
thin-film modules in 1998 and
plans to have product on the
market by 2003, comfortably
exceeding the original Centre
objectives.
SummarySummaryDirector:
Professor Martin Green (to 12/99)
Associate Directors:
Dr Armin Aberle (Thin-Film Devices) (from 11/98)
A/Professor Paul A. Basore (Multilayer Technology Commercialisation) (from 11/95 to 12/99)
Dr Christiana Honsberg (Buried Contact Cells) (from 1/99)
A/Professor Hugh R. Outhred (Systems)
Professor Stuart R. Wenham (Devices) (to 12/98)
Dr Jianhua Zhao (High Efficiency Cells) (from 1/99)
1999 24.7% efficient silicon solar cell*
24.5% efficiency cell on non-FZ substrate*
Aurora 101 solar car wins World Solar challenge with UNSW cells
1998 19.8% efficient “honeycomb textured” multicrystalline cell*
24.5% efficiency silicon solar cell*
1997 18.2% efficient planar multicrystalline solar cell
22.7% efficient solar module*
1996 22.3% efficient solar module*
23.7% efficient large area cell (22 cm2)
1995 17.6% multijunction solar cell (32 microns active thickness)
1994 Development of multijunction solar cell
24.0% efficient silicon solar cell*
15.2% multijunction solar cell (20 microns active thickness)
720 mV silicon cell*
Development of rear floating junction devices with record voltages
1993 20.6% solar module* (first flatplate module to exceed 20% efficiency)
21.6% efficient large area cell (46 cm2)*
1992 717 mV silicon cell*
19.9% solar module*
1991 600 mV, 10% efficient thin film silicon cell (low T deposition)
TABLE S1: OUTCOMES
(PHOTOVOLTAICS SPECIAL RESEARCH CENTRE)
DEVICE RESEARCH (*DENOTES WORLD BEST)
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT S U M M A R Y
S7 �� S6
1999 Australia Prize awarded to Directors, Martin Green and Stuart Wenham
IEE Sir Lionel Hooke Award (M.A. Green)
Best Paper Award “Silicon Cells”, 11th Int. PV Conf., Hokkaido (J. Zhao et al.)
Special Award, International Collaboration, 11th Int. PV Conf., Hokkaido
1998 Overall Best Poster Award, 2nd World PV Conference, Vienna (M. Green)
Best Poster, “Fundamentals, Novel Devices, New Materials”, Vienna (M. Green)
Chairman’s Award, Australian Technology Awards
1997 Australian Achiever Award (M. Green)
Best Paper Award, Solar ’97 (P. Rowley et alia)
Best Student Paper, Solar ’97 (D. Remmer)
1995 IEEE J.J. Ebers Award “sustained technical leadership”, Washington (M. Green)
M.A. Sargent Medal “contributions through innovation” (M.A. Green)
Special Mention, Centre Posters at 13th European PV Conf., Nice
1994 Clunies Ross National Science and Technology Award (M. Green)
Best Poster, “Terrestrial Applications”, 1st World PV Conf., Hawaii
(M. Watt et al.)
1992 CSIRO External Medal (M. Green and S. Wenham)
EXTERNAL AWARDS
COMMERCIAL OUTCOMES
1999 Buried-contact technology transfer (Eurosolare)
1998 Pacific Solar announces pilot line commissioning (thin film cells)
BP Solar announces 20 MW, $57M plant in Sydney (buried contact cells)
Eurosolare licenses buried-contact technology
1995 Pacific Solar commences operation
Buried-contact cell most successfully commercialised in last 15 years
1994 Samsung licenses buried-contact technology
Thin-film on glass technology assigned to Pacific Solar
1993 550 kW system at Toledo, Spain using licensed technology
(world’s most efficient large PV system)
1992 First large system using licensed UNSW technology
(24 kW system using BP Solar modules in Berne, Switzerland)
1991 BP Solar releases “Saturn” module under licence
(highest efficient commercial module)
A I M S A N D O U T C O M E S
S9 �
development of the approach. A
new company, Pacific Solar, began
operation in Sydney in February,
1995 for this purpose. This exceeded
the initial Centre targeted timeline by
more than a year and addressed the
issue with much greater urgency
than originally contemplated. The
company began pilot production of
pilot line modules in 1998 (Figure
S4). In the same year, it was awarded
the Chairman's Award at the
Australian Technology Awards for
its efforts. The company presently
plans to have the new technology
commercially available by 2003.
The third aim of
the Centre lay in
the systems or
applica-
tions
a r e a .
The Centre
has successfully
achieved its goal
if greatly stimulating
these activities, while com-
mitting only quite modest
seeding funds for this purpose.
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT
� S8
Aims
The original aims of the
Centre were maintained
over its 9 year life. The
three aims were:
� To maintain and extend
Australia’s lead with conven-
tional silicon solar cells and
develop these to their full
potential;
� To develop silicon “thin film”
technology based on deposit-
ing silicon onto glass and to be
involved with one or more
commercial collaborators with
associated technology transfer
by 1996;
� To develop a co-ordinated set
of activities in the photo-
voltaics system area with these
to be funded largely from other
sources.
OutcomesThe Centre achieved its first aim
by extending its international
lead with first-generation, silicon
wafer based technology. By
demonstrating 24.7% efficiency
during 1999, the Centre exceed-
ed its international lead to over
5% relative, compared to 3% at
the commencement of the
Centre. The best confirmed effi-
ciencies from groups in Europe,
Japan and the United States at
present are 23.3%, 23.5% and
22.7% efficiency, respectively.
In the multicrystalline silicon cell
area, the Centre established a
value of 19.8% in 1998, more
than 6% relative above the next
best result internationally of
18.6%, established by the Centre
of Excellence in Photovoltaic
Research at the Georgia Institute
of Technology.
In the area of packaged modules,
the Centre established a new world
mark of 22.7%, well above the
next best result of 21.6% estab-
lished by the Honda Corporation
of Japan working with Sunpower
Corporation of the United States.
race record in the 1996 World
Solar Challenge, the solar car
race across Australia. Powered
only by Centre cells, the car aver-
aged 90 km/hr across the 3,000
km course. Other solar cars that
have won the Challenge using
Centre cells included the Spirit
of Biel and Aurora 101, with
Centre cells used on the
Aims and OutcomesAims and OutcomesSunrayce, where competitors were
restricted to inexpensive commercial
cells, 9 of the 10 top cars were pow-
ered with cells made under licence to
the Centre. The sixth placed car not
using Centre cells won a special award
for doing so well with such a handi-
cap. In the next race, competitors
were restricted to US-made cells to
broaden the supply base, since the
cells supplied by BP Solarex were
unique in performance.
During the life of the Centre, BP
Solarex successfully commercialized
first-generation Centre technology.
Figure S1 shows the first large instal-
lation of these cells at the Spanish
utility, Union Fenosa, site near Toledo
in 1994. At the time, this was
Europe's largest photovoltaic system.
Over recent years, the cells made in
highest volume in Europe have been
made under license to the Centre. In
1998, BP Solarex announced plans
for establishing the world's largest
solar cell manufacturing facility in
Sydney (Figure S3). With the subse-
quent merger of BP and Amoco,
these plans have been shelved,
although European production of
Centre cells is being expanded.
Other commercialisation success
has been with cells manufactured
for use on spacecraft. Cell tech-
nology first demonstrated by the
Centre has now been commer-
cialised by Tecstar Corporation
of California and the Sharp
Corporation of Japan. An
Australian consortium also com-
pleted a feasibility study of space
cell manufacture and array
assembly in Australia using
Centre cell technology.
Considerable success has also been
achieved with more recently devel-
oped second-generation technolo-
gy, involving the deposition of very
thin films of silicon onto glass sub-
strates. After showing that the main
challenge in this area was deposit-
ing films of the quality required for
good cell performance, the Centre
announced the filing of patents on
a new cell structure able to tolerate
low quality material. This attracted
international attention at the time,
being hailed as a “conceptual
breakthrough” and featuring in the
New York Times, Time Magazine,
Scientific American and a range of
other newspapers and magazines.
The new cell designs gave
a high level of confidence
in the viability of the
silicon thin-film
approach. This
resulted in a
major initia-
tive by Aus-
tralian utility,
Pacific Power, to
fund the commercial
FIGURE S2: HONDA DREAM SOLAR CAR.
FIGURE S1: CENTRE DIRECTOR, MARTIN GREEN,
AT EUROPE'S THEN LARGEST PHOTOVOLTAIC PLANT IN TOLEDO,
USING CELLS MADE UNDER LICENSE TO THE CENTRE.
FIGURE S3: ARTIST'S IMPRESSION OF THE PROPOSED BP SOLAREX
FACILITY IN SYDNEY (ARTWORK COURTESY OF BP SOLAREX)
FIGURE S4: PACIFIC SOLAR PILOT LINE MODULE
(PHOTOGRAPH COURTESY OF PACIFIC SOLAR PTY LTD).
This clear lead in cell perform-
ance has been used to advantage
in solar car racing. Figure S2
shows the Honda Dream, the
best performing solar car to
date, that set an as yet unbeaten
winning car in three of the five
Challenges to date.
Even greater success in this area
has been enjoyed by Centre licens-
ee, BP Solarex. In the 1993
A I M S A N D O U T C O M E S
S11 �
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT
� S10
The University is now widely recog-
nised for its photovoltaic systems
activities, receiving major support
from Pacific Power, Energy-
Australia, Australian aid agencies
and the Australian Co-operative
Research Centre for Renewable
Energy (ACRE) for this work over
the present reporting period.
Highlights include the installa-
tion of the first grid-connected
photovoltaic systems in New
South Wales at the University's
Solar Research Facility at Little
Bay. This has now been operat-
ing satisfactorily for many years.
Another highlight has been the
establishment of a Design
Assistance Division to provide
advice, not otherwise readily
available, to prospective users of
photovoltaic systems. Major
installations in which it has
played a role include a 4 kilowatt
hybrid system installed by
National Parks and Wildlife on
Montague Island, off the New
South Wales coast, a 4 kW
hybrid system at Green Cape
National Park on the New South
Wales far south coast, as well as
many smaller projects. The
Centre has also participated in
the development and running of
accreditation courses for the
Solar Industries Association of
Australia. It has also acted as a
focus for the development of
standards for inverters for grid-
connected photovoltaic systems,
working with various parties in
connection with providing pho-
tovoltaic power to each of the
more than 600 homes compris-
ing the Athletes' Village for the
Sydney 2000 Olympics. The
Centre has also developed and
run a variety of short courses
including the first international
internet courses on photovoltaic
devices and systems.
Independent confirmation of the
quality of this systems work stim-
ulated by the Centre comes from
a best paper award in “ Terrestrial
Applications Area” at the 1st
World Conference on Photo-
voltaic Energy Conversion in
Hawaii in December, 1994, an
invited plenary session paper for
system researcher, Dr Muriel
Watt, at the 26th IEEE Photo-
voltaic Specialists Conference in
Washington in May, 1996, the
most highly rated systems paper
in the international journal
“Progress in Photovoltaics” over
the 1993-1995 period, and several
best paper awards in this area at
local conferences (see Table S1).
D E V I C E R E S E A R C H
S13 �
record” 24.7% with the PERL
cell approach, another key result
of the Centre was the demon-
stration of 19.8% efficiency on
low cost multicrystalline sub-
strates supplied by the Italian
company, Eurosolare. A striking
feature of these cells was the
use of a “honeycomb” texture
(Figure S6) to play the same role
as the “inverted pyramids” in
the crystalline cells (the latter
technique could not be used
with multicrystalline silicon due
to the lack of a well defined ori-
entation template). Another fea-
ture of multicrystalline silicon
cells is the spatial non-uniformi-
ty of cell response. This is
demonstrated in Figure S7
where the different colours
show regions of different
response of the 19.8% efficient
cell due to crystallographic
defects, particularly grain
boundaries.
Other key results in this high-
efficiency cell strand of activity
include the demonstration of
Buried ContactSolar Cells
Project Leader:
Dr Christiana Honsberg
Other Contributors:
Dr Benjamin Chan, Dr Chee Mun Chong,
Dr Jeff Cotter, Dr Ximing Dai,
Dr Kerrie Davies, Dr Ebong Abesafreke,
Dr Sean Edmiston, Alan Fung,
Seyed Ghozati, Professor Martin Green,
Amal Khouri, Linda Koschier,
Keith McIntosh, Dr Hamid Mehrvarz,
Stephen Pritchard, Bryce Richards,
Jiqun Shi, Alexander Slade, Yinghui Tang,
Dr Michael Taouk, Bernhard Vogl,
Professor Stuart Wenham, Yan Wu,
Rudong Xiao, Fei Yun,
Dr Fuzu Zhang, Dr Jianhua Zhao,
With the success of BP Solarex in
commercializing the buried contact
cell, this cell became the most success-
fully commercialized new solar cell
technology over the grant period. The
cell structure, shown in Figure S9, was
developed as an attempt to incorpo-
rate some of the high efficiency
features demonstrated in the previous
high efficiency strand of the work
into a low cost commercial cell.
the first 20% efficient photo-
voltaic module from any materi-
al in 1993. This was subsequent-
ly increased to 22.7% in 1996 by
the use of the innovative cell
shingling approach.
Other highlights include the
fabrication of large quantities of
high performance solar cells for
both the 1993 and 1996 World
Solar Challenges, the major
international solar car race from
Darwin to Adelaide. For the
1996 event, almost 20,000
PERL cells were fabricated with
cell efficiency ranging up to
24%. Figure S8 shows the cell
efficiency distribution accumu-
lating after each month of pro-
duction during 1996. The graph
shows a steady refinement in the
performance of the cells as
more experience was gained
with the manufacture. Over 60%
of the cells demonstrated
efficiencies above 23%. Most
of these cells are higher in
performance than those made in
any laboratory around the world
giving the Centre the record for
the best 10,000 silicon cells
ever made!
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High EfficiencyCells
Project Leader:
Dr Jianhua Zhao
Other Contributors:
Dr Armin Aberle
Dr Pietro Altermatt
Dr Shijun Cai
Dr Ximing Dai
Professor Martin Green
Yinghui Tang
Dr Aihua Wang
Professor Stuart Wenham
The PERL (passivated emitter,
rear locally-diffused) cell of
Figure S5, first successfully
implemented during the early
years of the Centre's operation ,
has been the mainstay for most of
the improvements demonstrated
during the life of the Centre.
Key electronic features are the
almost complete enshroudment of
the cell in a thermally grown oxide
to give the lowest possible rates of
surface recombination, the use of
small area contacts to reduce
metal-semiconductor recombina-
tion rates, the use of highly doped
diffused regions in these contact
regions for the same purpose, and
the selection of processing condi-
tions to ensure the preservation or
even enhancement of material
quality, as measured by minority
carrier lifetime. Particular attention
has been given to the quality of the
oxide-silicon interface with an
atomic hydrogen treatment giving
best results to date. This treatment
is based on the local generation of
this atomic hydrogen by reaction
of hydrogen ions in the oxide with
an aluminum capping layer.
Optically, the inverted pyramids on
the top surface reduce reflection
loss. Light is also coupled in
obliquely across the cell, increasing
prospects for absorption for weak-
ly absorbed wavelengths. The
metal rear contact serves as an effi-
cient reflector of light reaching the
rear, particularly when displaced by
the low refractive index oxide layer,
as shown. After rear reflection,
weakly absorbed light approaches
the top surface from within the
cell, with about half striking pyra-
mid faces that couple it out. The
rest strikes other pyramid faces at
angles that are sufficiently oblique
that this light is reflected by total
internal reflection. This light is
very effectively “trapped” into the
cell. Optically, this makes the cell
appear much thicker than its actual
thickness - up to 40 times thicker
for some of the Centre's experi-
mental devices.
The effectiveness of this “light
trapping” approach was demon-
strated by another key result
from the Centre. This was the
demonstration of 21.5% effi-
ciency for a cell that was only 48
microns thick, almost 10 times
thinner than the Centre's normal
high performance devices. This
provides experimental support
for the view that such “light trap-
ping” allows reasonable per-
formance to be obtained from
silicon films that are much thin-
ner than previously thought
feasible.
Apart from increasing silicon
cell efficiency to a “world
Device ResearchDevice Research
FIGURE S5: PERL SILICON SOLAR CELL.
FIGURE S6:
HONEYCOMB TEXTURING OF
MULTICRYSTALLINE CELL.
FIGURE S8: EFFICIENCY DISTRIBUTION OF PERL CELLS FOR
1996 WORLD SOLAR CHALLENGE.
FIGURE S7:
SPATIAL RESPONSE OF
19.8% EFFICIENT MULTI-
CRYSTALLINE CELL.
S15 �
ticrystalline silicon wafers. For
low quality wafers, the perform-
ance benefit of the standard
selective emitter feature of the
buried contact cells becomes
less important because the cell
open-circuit becomes dominat-
ed by recombination in the bulk
regions of the cells rather than
at the contacts.
Work with the simplified
sequence has shown that open
circuit voltage in excess of 650
mV is achievable without the
use of the selective emitter dif-
fusion compared to values
approaching 700 mV with this
diffusion. A key element of the
simplified sequence is the use of
titanium dioxide, not only as an
antireflection coating but also as
a plating mask. Figure S10
shows experimental results
showing the use of titanium
dioxide with an underlying thin
silicon dioxide layer (13.5 nm)
allows surface recombination
velocities using this coating con-
sistent with open circuit voltage
in excess of 650 mV.
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Independent studies have shown that
this is not only the highest efficiency
cell in production, but is also the low-
est in cost under a similar set of eco-
nomic assumptions when compared
to use this technology (Figure S3).
Unfortunately, the merger of BP
and Amoco was announced shortly
after which resulted in these plans
being shelved.
Work during the reporting period
concentrated on two issues. One
was the simplification of the
buried contact sequence to allow
it to be more compatible with
solar cell processing lines based
on the existing cell technology.
The second was based on improv-
ing the performance of the rear
contact of the buried contact
solar cell to bring its performance
to a level where it more closely
matched that of the PERL cells.
The first-mentioned simplified
buried contact sequence uses a
number of innovations in the
processing sequence to reduce
the cost of fabrication while
retaining the efficiency advan-
tages of the buried contact tech-
nology. It is designed especially
for lower quality wafers such as
Czochralski grown and mul-
In the double-sided solar cell
sequence, a similar processing
sequence is applied to the rear
of the cell to bring its perform-
ance to a level consistent to that
of the top half of the cell
(Figure S11).
This structure proved more dif-
ficult to implement than expect-
ed due to the unanticipated
effects of shunt resistance upon
the rear cell performance. It was
realised that these were more
severe than in a standard solar
cell due to the lower effective
current densities attributable to
the rear contact. Extensive com-
puter modelling allowed these
effects to be fully understood
and experimental work made
significant progress towards
implementing high efficiency
devices. For example, solar cells
fabricated on high resistivity
wafers (5 �cm) demonstrated
voltages in excess of 650 mV
when illuminated from either
the front or rear surface. The
current response when illumi-
nated from the rear was 94% of
that when illuminated from the
front, a very high ratio for such
a simply fabricated cell. Use of
buried contacts on both front
and rear surface allowed mini-
mal obscuration of the cell sur-
face by these contacts. These
results demonstrate that a high
efficiency bifacial cell, using this
double sided structure, is techni-
cally feasible although still not at
the stage where it can be reliably
implemented commercially.
A second approach was also
explored as a way of improving
the rear contact to the cell. This
made use of a novel selective
solid phase epitaxial regrowth
process on the rear surface. This
project is now the subject of a
collaborative agreement with BP
Solarex and is being continued
as part of the program of the
Key Centre for Photovoltaic
Engineering (see separate Key
Centre Annual Report for a
more detailed account).
Another highlight in the buried
contact cell area was the fabrica-
tion of over 10,000 large area
buried contact solar cells for the
1993 World Solar Challenge. This
initiative made use of the pilot
line for buried contact cell fabri-
cation that had been established
for technology transfer to
licensees. An enhanced sequence
that combined the buried contact
top cell design with a photolitho-
graphically processed rear surface
contact resulted in cells being
fabricated with efficiencies up to
21.3%. Sixteen of these cells
were encapsulated locally into a
standard module by the former
Solarex Pty. Ltd. to produce a
world record efficiency of 19.8%
for a photovoltaic module.
D E V I C E R E S E A R C H
FIGURE S9: BURIED CONTACT SOLAR CELL.
FIGURE S10: EMITTER SATURATION CURRENT DENSITY MEASURED ON
MULTICRYSTALLINE WAFERS FOR VARIOUS SURFACE COATINGS. THE SOLID
LINES ARE SIMULATED WITH PC1D WITH THE INSET NUMBERS REPRESENT-
ING SURFACE RECOMBINATION VELOCITY. THE RED, PURPLE AND GREEN
SYMBOLS REPRESENT EXPERIMENTAL MEASUREMENTS OF SILICON DIOXIDE,
TITANIUM DIOXIDE, AND TITANIUM DIOXIDE OVER A THIN (13.5 NM)
SILICON DIOXIDE PASSIVATING LAYER, RESPECTIVELY.
FIGURE S11: DOUBLE-SIDED BURIED CONTACT SOLAR CELL.
to other wafer-based cell technologies
(T. Bruton, et alia, Conf. Record, 14th
European Photovoltaic Solar Energy
Conference, Barcelona, June/July,
1997, p. 11).
During the life of the Centre, the
first commercial installation of these
cells was installed on the funicular
railway leading to the Parliament
House in Berne, commissioned in
1992. The next large application was
for the Union Fenoza 1 MW plant in
Toledo, which was Europe's largest
photovoltaic installation at the time
(Figure S1). This was officially
opened in mid-1994. Since then, the
production output of the cells has
been greatly expanded at the
expense of more conventional tech-
nology previously used by BP
Solarex. An announcement was
made in late 1998 indicating the
imminent commissioning of the
world's largest solar cell manufactur-
ing facility here in Sydney which was
D E V I C E R E S E A R C H
S17 �
of silicon films. Shown in Figure S13are results for thin films prepared bythe Centre by sputtering, both beforeand after solid phase crystallization.Similar techniques were applied tomaterial produced by Pacific Solarunder a contract between the Centreand the company.
Another notable achievement was thedevelopment of electron-beam in-duced current (EBIC) technique forcharacterising experimental devices.Figure S14 shows this technique com-bined with electron microscopy toexplore grain boundary properties inmultilayer cells.
The third phase of activity hasinvolved the initiation of thin-filmprograms independent of the PacificSolar program. Good success has beenobtained with the metal induced crys-tallization of films deposited ontoglass. This is quite an unusual sequencein that, as shown in Figure S15, thedeposition sequence involved firstdepositing a layer of aluminum ontoglass and then a layer of similar thick-ness of amorphous silicon. After heat-ing for a short period, about 30 min-utes, at moderate temperatures around500o C the aluminum and siliconchange place as illustrated. Moreover,the originally deposited amorphous sil-icon layer is converted to large grainpolycrystalline material. This producescrystallites with very large lateraldimensions (typically above 20microns) which is unusual for the verylow processing temperatures involved.
The silicon layers are heavily dopedwith aluminum which reduces theirelectronic quality. Although it may bepossible to fabricate devices directlyinto these layers, work was also conducted that uses these layers as seeding layers for subsequent epit-axial growth of better quality siliconmaterial.
Another phase of activity involved thelaser crystallization of amorphous sili-con using copper vapour lasers. The
extremely high resolution that isachievable.
Fourier transform infrared spec-troscopy (FTIR) has also been devel-oped to allow characterisation of thesefilms. The technique is suitable fordetermining the hydrogen concentra-tion in these films as well as the filmthickness and refractive index as well asthe bonding configuration in amor-phous and polycrystalline silicon and insilicon nitride films deposited on sili-con wafers.
A more recent program is concernedwith careful documentation of theadvantages of the multilayer approachcompared to more traditional cellstructures. Multilayer cells are fabricat-ed using epitaxially grown layers oninert silicon wafer substrates. Con-ventional devices are grown by thesame approach. The performance isthen compared as a function of mate-rial quality, where this is adjusted bydamaging material by high energy pro-ton radiation. This allows the advan-tage of the buried contact approach tobe quantified as a function of materialquality. The clear advantage of themultilayer cell has become apparentduring this work. Due to the presenceof multiple junctions, a larger fractionof the volume of the cell remainsactive even when material quality isextremely poor.
use of excimer laser crystallization ofsilicon films is well established in theactive matrix liquid crystal display area.The films used in the latter application,however, are too thin for use in photo-voltaics where layers of several micronthickness are required. The wavelengthof the copper vapour laser is muchmore suited to the crystallization ofthese films and good preliminaryresults were demonstrated during thiswork. Other techniques developedduring this work include the high reso-lution electron beam induced current(EBIC) imaging of polycrystalline sili-con cells. Because the grain size insuch material may be only of the orderof a micron, much higher resolutionthan normally obtained with the EBICtechnique is required.
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Thin-Film Solar Cells
Project Leader:
Dr Jurek Kurianski (to 8/93)
Dr Alistair Sproul (to 11/98)
Dr Armin Aberle (from 11/98)
Other Contributors:
Dr Pietro Altermatt, A/Professor Paul
Basore, Robert Bardos, Dr Matthew
Boreland, Dr Patrick Campbell,
Dr Benjamin Chan, Professor Martin Green,
Dr Mark Gross, Dr Stephen Healy,
Dr Mark Keevers, Daniel Krcho, Oliver
Nast, Dirk-Holger Neuhaus, Kazuo Omaki,
Dr Tom Puzzer, Dr Stephen Robinson,
Dr Michael Taouk, Professor Stuart
Wenham, Dr Guang Fu Zhang
The thin-film solar cell work conduct-ed at the Centre can be divided intothree phases. The first phase predatedthe formation of Pacific Solar in early1995, and was involved with the inves-tigation of techniques for the deposi-tion of silicon on glass and the devel-opment of appropriate cell structuresto allow high performance from suchdeposited material. With the forma-tion of Pacific Solar, many of the staffinvolved with this work were secondedto the new company to help develop asequence suitable for pilot production.The key role for the Centre thenbecame one of supporting this com-mercialisation effort by undertakingdetailed characterisation of the materi-al and devices being fabricated byPacific Solar. In the third and mostrecent phase, the Centre has re-established thin-film programs inde-
pendent of those being conducted atPacific Solar.
Work in the first phase of activitiesattempted to prepare high quality poly-crystalline films of silicon on glass. Atthis stage, it was believed that extreme-ly good quality material would berequired to reach reasonable levels ofcell performance and the emphasiswas on techniques consistent withobtaining such good quality. Con-siderable progress was made with solu-tion growth of silicon films onto glassand with the use of metal-inducedcrystallisation of silicon films, duringthis period.
There was a change in emphasis in thiswork with the invention of the multi-layer cell of Figure S12. By arrangingto have multiple junctions connectedin parallel dispersed throughout thecell volume, it was possible to makethe whole volume photovoltaicallyactive regardless of the quality of sili-con material. This opened up a farwider range of material depositionpossibilities, since the originally anticipated high quality was no longeressential.
Proof of concept work conducted bythe Centre established the high effi-ciency potential of this approach withworld record efficiency of 17.6%established for a thin multilayer cellgrown on a good crystallographicquality, but electronically inert, siliconwafer template.
In 1995, Pacific Solar came into oper-ation and began its own programbased on the prior work conductedwithin the Centre. Key researchersfrom the Centre were seconded toassist in this program. Steps were takento allow the company to develop thistechnology with an appropriate levelof commercial confidentiality. Accord-ingly, the Centre program entered thesecond phase where most of theCentre's work dealt with characterizingmaterials and devices fabricated byPacific Solar. Notable achievementsduring this period included the devel-opment of optical techniques formeasuring the absorption properties
FIGURE S12: MULTILAYER
SOLAR CELL.
FIGURE S13: ABSORPTION CO-EFFICIENT FOR SPUTTERED AND ANNEALED
SILICON FILMS, SHOWING DEFECT ABSORPTION ABOVE AND BELOW THE
BANDGAP. THE C-SI DATA IS TAKEN FROM THE WORK OF GREEN.
FIGURE S15: SEM PICTURE OF:
(A) THE A-SI/AL/GLASS STRUC-
TURE BEFORE ANNEALING AND
(B) THE AL(+ SI)/POLY-SI/GLASS
STRUCTURE RESULTING FROM A
30 MIN. ANNEAL AT 500�C.
S14: ELECTRON BEAM INDUCED
CURRENT (EBIC) IMAGE OF A
5 LAYER MULTIJUNCTION CELL
GROWN ON A POLYCRYSTALLINE
SILICON SUBSTRATE.
(IMAGE BY DR TOM PUZZER).
FIGURE S16: HIGH-RESOLUTION
EBIC IMAGE OF INTERSECTING
GRAIN BOUNDARIES IN A LARGE-
GRAINED POLYCRYSTALLINE
SILICON SOLAR CELL.
The approach taken is to use low ener-gy electron beams (typically 2-5 keV)instead of the more typical 20-30 keV.Lower energy means the excitationvolume within the silicon is smallerand can have a diameter of less than 1micron. Figure S16 shows a high reso-lution EBIC image of intersectinggrain boundaries in a large grain poly-crystalline silicon film showing the
SUPPORTING FUNDAMENTAL WORK
S19 �
of some of the activity under
the new Special Research Centre
for Third Generation Photo-
voltaics. It also led to new infor-
mation on the properties of
rare-earth metals in silicon and
the mechanisms for charge
interchange between rare earth
atoms and the silicon crystal
in collaborative work with FOM
Institute for Atomic and
Molecular Physics of the
Netherlands. Recombination in
solar cell depletion regions was
also extensively studied due to
its relevance to multilayer cell
design. The increased under-
standing gained led to new
design concepts allowing min-
imisation of this recombination
effect. Other work involved
development of a range of tech-
niques for the electrical and
optical characterisation of solar
cells and the constituent materi-
als. For example, FTIR allowed
characterisation of impurities,
free carrier behaviour and the
properties of thin and layered
samples. Figure S18 shows
an infrared photoconductivity
spectrum of a lightly boron
doped floatzone silicon wafer at
a temperature of 20K. The
sharp lines represent electronic
bination coefficients at high
excitation levels. The role of
excitons upon room tempera-
ture performance of silicon
solar cells was also explored
leading to new insights into
minority carrier behaviour in
solar cells and other semicon-
ductor devices.
transitions while the broad max-
imum is due to photo-ionization
of impurities in the material.
Other work involved in investi-
gation of second order effects
of significance in device design.
This included the effect of dop-
ing upon the density of states in
silicon material and the behav-
iour of the silicon Auger recom-
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Project Leader:
Dr Alistair Sproul (to 11/98)
Dr Armin Aberle (from 11/98)
Other Contributors:
Dr Pietro Altermatt
Donald Clugston
Dr Richard Corkish
Dr Sean Edmiston
Roland Einhaus
Frank Geelhaar
Professor Martin Green
Dr Om Kumar Harsh
Dr Gernot Heiser
Dr Christiana Honsberg
Yidan Huang
Dr Mark Keevers
Daniel Krcho
Marco Lammer
Axel Neisser
Holger Neuhaus
Andreas Stephens
Dr David Thorp
Professor Stuart Wenham
A range of supporting funda-
mental work both assisted the
previous device research pro-
grams and also benefited from
the availability of devices and
processing techniques of unique
capabilities. In the latter area,
significant results were achieved
in defining new values for vari-
ous silicon material parameters
of relevance to photovoltaics
and the broader microelectron-
ics area. This work has been
made possible by the high quali-
ty of device processing available
to the Centre through its device
research programs. Early in the
Centre's life, specially construct-
ed diodes were used to derive
new experimental values for sili-
con's intrinsic carrier concentra-
tion. Similar capabilities allowed
new values to be extracted for
silicon's minority carrier mobili-
ty as a function of doping level
in the substrate. Similarly, high
performance cells provided an
ideal test vehicle for measuring
the absorption coefficient of sil-
icon to unprecedently small val-
ues (Figure S17). Band absorp-
tion processes at photon ener-
gies well below the bandgap
were detected with the energy
up to 4 phonons contributing to
the absorption processes.
Another large strand of activity
has involved the numerical mod-
elling of silicon solar cells. The
Centre has been fortunate in
having access to some of the
most advanced silicon device
simulators internationally and
has, in fact, contributed to the
further development of these
simulation packages. For one
dimensional simulation, the
Centre has contributed to the
recent development of the
international standard simulator,
PC1D, and acted as distributor
of this improved software pack-
age. For 2D and 3D simulations,
the Centre has worked with
ETH, Zurich on the develop-
ment of Dessis. This package
was used by the Centre for some
of the first ever 3D solar cell
simulations, which were of great
benefit in refining the design of
experimental devices.
The impurity photovoltaic effect
was extensively studied during
the grant period and led to new
insights into important features
of such multiple photon
absorption schemes. The inter-
est created by this work has
been at least partly responsible
for interest in the multi-band
structures that form the focus
Supporting Fundamental WorkSupporting Fundamental Work
FIGURE S17: ABSORPTION COEFFICIENT OF SILICON.
FIGURE S18: INFRARED PHOTOCONDUCTIVITY SPECTRUM OF A BORON
DOPED (100 �CM) FLOAT-ZONE SILICON WAFER AT APPROXIMATELY 20K.
S Y S T E M S R E S E A R C H
E D U C A T I O N , T R A I N I N G
S21 �
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Project Leader:
A/Professor Hugh Outhred
Other Contributors:
Stillisn Atanassov, Fabio Barone,
Dr Trevor Blackburn, Dr Kevan Daly,
Mark Ellis, Dave Gilbert, Mark Hancock,
Greg Harbidge, Dr John Kaye, Erik Keller,
George Kinnell, Robert Largent,
Iain MacGill, Dr Adelle Milne,
Professor Ian Morrison, Dorothy Remmer,
David Roche, Professor Bent Sorensen,
Ted Spooner, Dr Qi Su, Dr Dean Travers,
Dr Muriel Watt
One of the Centre's original aims
was to stimulate a range of co-ordi-
nated photovoltaic systems activities
at the University using funding
largely from other sources. The
Centre has been remarkably success-
ful in achieving these aims. Com-
bined with the fortunate timing of
the Centre's inception, the Centre
has had an impact in the systems
area out of all proportion of the
seeding funds expended to stimulate
these activities.
Success of the Centre in this area was
greatly enhanced by major grants
early in the Centre's history from
local power companies, Pacific Power
and EnergyAustralia. Both compa-
nies have gone on to a more substan-
tial involvement in photovoltaics,
using the experience gained through
funding Centre activities as the base
for these further activities. As men-
tioned earlier, Pacific Power is now
the major shareholder in Pacific
Solar, a company formed specifically
to commercialise the Centre's thin
film polycrystalline silicon-on-glass
technology, with a focus towards
marketing residential photovoltaic
systems. EnergyAustralia was one of
the first power companies to intro-
duce “green energy” schemes into
Australia through its Pure Energy
scheme. EnergyAustralia has com-
missioned the installation of the
largest photovoltaic system in the
southern hemisphere at Singleton as
a result of this program. It is unlikely
that either company would have been
as heavily involved in photovoltaics
without their prior interaction with
the Centre.
The Centre was also heavily
involved with another major pho-
tovoltaics initiative. This was the
use of photovoltaics for the
Athletes' Village for the Sydney
2000 Olympics. Centre Director,
Martin Green, participated in
early meetings formulating fea-
tures of the ultimately successful
bid tender by Mirvac/Lendlease.
Ted Spooner has been actively
involved in the development of
guidelines for the development of
inverters for use in such grid-con-
nected residential systems as well
as being heavily involved in test-
ing of the inverters used in the
installation, to ensure they comply
with these guidelines. The success
of this initiative, in turn, has
undoubtedly contributed to the
Government's announcement of
a $31 million scheme to subsidise
the more widespread use of resi-
dential photovoltaic systems in
Australia.
The main test bed for system testing
is at the University's Solar Research
Facility at Little Bay. Here, there are
two 2 kW arrays, one using
monocrystalline silicon and the sec-
ond using multicrystalline silicon as
well as a 1 kW triple junction amor-
phous silicon cell array (see Facilities
section of this publication). These
arrays can be configured to be grid-
connected or to be used for stand-
alone system experiments.
Researchers affiliated with the
Centre have contributed to areas
across the breadth of issues relevant
to photovoltaic applications. Areas
of special interest have been elec-
tricity industry restructuring and
regulation, institutional and environ-
mental issues relating to the use of
photovoltaics, power system interac-
tion and economics, system hard-
ware and performance monitoring,
remote area power supplies, residen-
tial photovoltaics and the develop-
ment of standards.
Systems ResearchSystems Research
FIGURE S19: PART OF THE OLYMPIC ATHLETES' VILLAGE
SHOWING ROOF-MOUNTED PHOTOVOLTAICS.
Sydney (Figure S21). Data from the
Centre's Little Bay installation is
accessible via the internet in a “virtu-
al power station” concept for schools
without their own system.
During the grant period, the
Centre also supported technology
transfer through Unisearch Ltd.,
the commercial arm of the
University. As well as the activi-
ties with Pacific Solar previously
mentioned, the Centre provided
support to licensees of wafer-
based technology BP and Solarex,
now BP Solarex, as well as
to Telefunken Systeme Technik
(now ASE GmbH), Central
Electronics Ltd. (India), Euro-
solare (Italy), and Samsung
(Korea). This often involved
training on the Centre's pilot line
during extended visits by a team
from the licensee's staff as well as
visits to the licensee's site by
Centre staff.
technical report for the 1996 World
Solar Challenge commissioned from
the Centre and, in 1999, by
“Crystalline Silicon Solar Cells:
Advanced Surface Passivation and
Analysis” by Dr Armin Aberle.
A number of international short
courses were delivered during the
grant period, such as the three-week
intensive course in Applied Photo-
voltaics delivered to Indonesian
BPPT staff during 1998. For local
practitioners, the Centre was also
involved with the development and
presentation of training courses for
photovoltaic systems for the Solar
Energy Industries. The Centre also
has pioneered leading-edge technolo-
gy for course presentation, such as
the interned-based “Applied Photo-
voltaics” course run during 1998 and
1999. Course material was supplied
via a Centre supported CD-ROM,
with tutoring over the internet for
the largely international participants
in this course.
Apart from lectures to high school
and gifted students and hosting
Centre visits for such students, a
1 kilowatt array was installed on the
roof of Fort Street High School in
Academic Contributors:
Dr Armin Aberle,
Dr Jeff Cotter,
Professor Martin Green,
Michelle Guelden,
Dr Christiana Honsberg,
Dr John Kaye,
A/Professor Hugh Outhred,
Dr Rodica Ramer,
Professor Stuart Wenham,
Dr Muriel Watt
Business Manager:
David Jordan (to 8/97)
Mark Silver (from 8/97)
Other Contributors:
Dr Stuart Bowden, Dr Kerrie Davies,
David Roche, Dr Ted Szpitalak,
Michael Taouk, Michael Willison,
Dr Jianhua Zhao
The major education activities of the
Centre addressed postgraduate
education, although these broadened
out to address undergraduate and
high school students, and the wider
community.
Postgraduate education occurred via
thesis research supervision and
through the development and pres-
entation of formal postgraduate
courses. A total of 34 postgraduate
theses were completed during the
grant period, of which 22 were at the
doctoral level. A listing of these the-
ses for the 1991-1999 period can be
found in the publications list at the
rear of this report. A Master of
Engineering Science course strand
for students wishing to specialise in
photovoltaics was also developed.
The lecture notes for the correspon-
ding courses and parallel courses
offered to final year undergraduate
students were expanded out to form
the basis of three textbooks released
by the Centre as a trilogy in 1995
(Figure 20). These were joined in
1997 by the “Speed of Light”, the
FIGURE S20: CENTRE TEXTBOOK
TRILOGY RELEASED IN 1995.
Education,Training & Technology Transfer
FIGURE S21: FORT STREET
HIGH SCHOOL WITH 1 KW PV
SYSTEM VISIBLE ON ROOF.
Education,Training & Technology Transfer
E X T E R N A L C O N T A C T S
F I N A N C I A L S
S23 �
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT
� S22
EEXXTTEERRNNAALL RREELLAATTIIOONNSS MMAANNAAGGEERR::
Michael Willison (to 3/94)
Michelle Guelden (from 3/94 to 3/96)
David Roche (from 3/96 to 10/98)
Robert Largent (from 10/98)
Design Assistance Div. Manager:
Robert Largent
Other Contributors:
Dr Christiana Honsberg,
David Jordan, plus many other staff
The Centre's external contacts were
wide and varied, ranging from links
to other local and international
research institutes to providing
advice on photovoltaic use to mem-
bers of the community previously
not familiar with this technology.
Good links were established with
other research groups in Australia
and overseas interested in photo-
voltaics, including most major labo-
ratories, with staff interchange
involved in several cases. Visitors to
the Centre for prolonged periods
included researchers from China,
Denmark, Germany, Japan, Ger-
many, Netherlands, Switzerland and
the USA. As well as students from
other Australian universities, the
Centre additionally attracted post-
graduate students from China,
Germany, Iran, Japan, New Zealand,
Nigeria, Philippines, Switzerland,
Thailand, the UK and the USA.
The Centre's External Relations
Section and the Design Assistance
Division provided the main routes for
formal contact with the wider com-
munity, apart from those involving
formal education, or training or trans-
fer of the Centre's device technology.
Major installations in which the
Design Assistance Division has played
a role include a 4 kilowatt hybrid
system installed by National Parks and
Wildlife on Montague Island (Figure
S22), off the New South Wales coast,
a 4 kW hybrid system at Green Cape
National Park on the New South
Wales far south coast, as well as many
smaller projects.
Some of these smaller projects have
involved assisting local artists, such
as Allan Giddy and Joyce
Hinterding, in incorporating photo-
voltaics into their art. Figure S23
shows Allan Giddy's Ice Heart sculp-
ture on Tamarama Beach, Sydney in
1999 using photovoltaics to cool a
block of ice at the apex of the
pyramid in the centre of the
photograph. Joyce Hinterding’s
Koronatron exhibited in Ober-
hausen, Germany between April
and October, 1996, was powered by
nearly a kilowatt of photovoltaics.
External ContactsExternal Contacts
FIGURE S22: MONTAGUE ISLAND: 4 KWP PV
ARRAY USED TO POWER ISLAND COMMUNITY.
FIGURE S23: ALLAN GIDDY’S
ICE HEART SCULPTURE ON
TAMARAMA BEACH, SYDNEY.
The total grant under the ARC
Special Research Centres Scheme
was $8,850,234 over the 1991-1999
timeframe, averaging approximately
$1 million/year in current dollars.
The original plan for the Centre was
to use this funding to provide infra-
structure for Centre operations, seed-
ing funds to bring projects to the
stage where they could attract exter-
nal funding, and complementary
funding to improve the viability and
scope of externally supported proj-
ects. In this plan, most of the funds
for Centre activities were to be from
additional external grants with the
ARC funds targeted to account for
less than 45% of Centre expenditure.
This target has been achieved, with
the Special Research Centres Grant,
representing only about 40% of
funds expended on Centre-related
activities. Apart from other ARC
schemes such as the Research
Fellowship and Large and Small
Grant Schemes, substantial external
funding has been received from
Pacific Solar, the former Energy
Research and Development
Corporation, Pacific Power, the
NSW Office of Energy, Sandia
National Laboratories, Energy
Australia, the Humboldt Foundation,
and other Australian government
departments (such as DITARD,
AIDAB). The University of New
South Wales was also a major con-
tributor in many ways, particularly
through its Major Equipment and
Infrastructure Grants.
Additionally, commercial activities
through Unisearch Ltd generated
substantial additional income such
as from licence fees, royalties, con-
sulting and the sale of high per-
formance solar cells for solar car
racing. Most of this income has
been invested in the Centre's tech-
nology transfer facilities in
Bay Street, Botany. These
facilities have generated income
from rent for the Centre and will
provide future support for Centre
related activities.
Figure S24 shows the breakdown of
the expenditure of ARC Special
Research Centre funds of $8,850,234
by expenditure category. The largest
single expenditure category has been
salaries that accounted for close to
40% of overall expenditure. A simi-
lar amount was spent on materials,
generally those required for provid-
ing operational and laboratory infra-
structure. Smaller amounts were
expended on equipment and travel.
Figure S25 shows the breakdown by
project area of ARC Special
Research Centre funds. The ARC
funds have been used primarily to
provide infrastructure by supporting
the operation, maintenance and
development of Centre laboratories
and facilities with a smaller amount
used as seeding funds for system
and device research activities.
FinancialsFinancials
FIGURE S24: BREAKDOWN OF EXPENDITURE OF
ARC SPECIAL RESEARCH CENTRE FUNDS BY CATEGORY.
FIGURE S25: BREAKDOWN OF
EXPENDITURE OF ARC SPECIAL
RESEARCH CENTRE FUNDS BY
PROJECT AREA.
P U B L I C A T I O N S
S25 �
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Surface Passivation of Crystalline
Silicon Solar Cells”, Solar Energy
Materials and Solar Cells (in press).
Altermatt, P.P., Sinton, R.A. and
Heiser, G., “Improvements in
Numerical Modelling of Highly
Injected Crystalline Silicon Solar
Cells”, Solar Energy Materials and
Solar Cells, (in press).
Bremner, S., Corkish, R. and
Honsberg, C.B., “Detailed Balance
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Solar Cells - Advanced Surface
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Corkish, R., “Limits to the
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Debuf, D., “Analysis of Multi-
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Krimwongrut, P., “Disturbances in
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Roche, D., “Solar Mismatch
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Altermatt, P.P., “Two Dimensional
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Dai, X., “High Efficiency N-Type
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Ebong, A., “Double Sided Buried
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Zhang, W., “Liquid Phase
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Robinson, S.J., “Non-Ideal”
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Davies, K., “Hollow Cathode
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Hancock, M., “A New Method for
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Einhaus, R., “Design of a New
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Jurgens, J., “Examination of Loss
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Zhang, F.Z., “Buried Contact
Silicon Concentrator Solar Cells”,
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Ghozati, S., “High Efficiency
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Bowden, S., “A High Efficiency
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Keevers, M.J., “Improved Perfor-
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Zheng, G.F., “High Efficiency
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Edmiston, S.A., “Modelling of
Thin Film Crystalline and
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Harsh, O.K., “Involvement of
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Altermatt, P.P., “The Charac-
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Zhao, J., Wang, A., Zhang,
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Nast, O., Brehme, S., Pritchard,
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Applied Physics, (in press).
Neuhaus, D.H., Altermatt, P.P. and
Aberle, A.G., “Determination of
the Density of States in Heavily
Doped Regions of Silicon Solar
Cells”, Solar Energy Materials and
Solar Cells, (in press).
Paretta, A., Sarno, A., Tortora, P.,
Yakubu, H., Maddalena, P., Zhao, J.
and Wang, A., “Angle-Dependent
Reflectance Measurements on
Photovoltaic Materials and Solar
Cells”, Optics Communications,
(in press).
Rohatgi, A., Doshi, P., Moschner, J.,
Lauinger, A., Aberle, A.G. and
Ruby, D.S., “Comprehensive Study
of Rapid, Low-Cost Silicon Surface
Passivation Technologies”, IEEE
Trans. Electr. Dev. (April 2000).
Schumacher, J.O., Altermatt, P.P.,
Heiser, G. and Aberle, A.G.,
“Application of a New Bandgap
Narrowing Model to the Numerical
Simulation of Saturation Current
Densities of Phosphorus Doped
Silicon Emitters”, Solar Energy
Materials and Solar Cells, (in press).
Wenham, S.R., Honsberg, C.B.,
Cotter, J., Largent, R., Aberle, A.G.,
Spooner, T. and Green, M.A.,
“Opportunities Arising through
Rapid Growth of the Photovoltaic
Industry”, Solar Energy Materials
and Solar Cells (in press).
P U B L I C A T I O N S
S29 �
and Engineering Conference,
Sapporo City, September, 1999,
pp. 525-526.
Wenham, S.R. and Aberle, A.G.,
“Photovoltaic Technology at the
University of New South Wales”,
Workshop Proceedings, Workshop
on Renewable Energy (Perth,
Australia, Feb. 1999), pp. 34-39.
Zhao, J., Wang, A. and Green,
M.A., “UNSW Experiments on
SEH MCZ, CZ (Ga), CZ (B) and
FZ Si Substrates”, Final Report,
Shin-Etsu Handotai Corporation
and Tokyo University of Agri-
culture and Technology, August,
1999 (10pp.).
Zhao, J., Wang, A. and Green,
M.A., “High Efficiency PERL
Silicon Solar Cells on FZ, MCZ
and CZ Substrates”, Tech. Digest,
11th International Photovoltaic
Science and Engineering Con-
ference, Sapporo, September,
1999, pp. 557-558.
Zhao, J., Wang, A. and Green,
M.A., “24.5% Efficiency PERT
Silicon Solar Cells on MCZ
Substrates”, Tech. Digest, 11th
International Photovoltaic Science
and Engineering Conference,
Sapporo, September, 1999, p. 979.
Zhao, J., Wang, A. and Green,
M.A., “24.7% Efficient PERL
Silicon Solar Cells and other
High Efficiency Solar Cell and
Module Research at the Uni-
versity of New South Wales”,
ISES Solar World Congress,
Jerusalem, Israel, July, 1999.
Zhao, J., Wang, A. and Green, M.A.,
“Technical Report Describing
UNSW Experiments on SHE
MCZ, CZ (Ga), CZ (B) and FZ
Silicon Substrates”, Workshop on
Light Degradation of Carrier
Lifetimes in CZ-Si Solar Cells -
International Joint Research, 11th
International Photovoltaic Science
and Engineering Conference,
Sapporo, Japan, September, 1999.
Zhao, J., Wang, A. and Green,
M.A., “Recent Performance Im-
provement of High Efficiency
Silicon Solar Cells”, Proceedings of
Solar '99 Conference, Geelong,
December, 1999.
Zhao, J., Wang, A. and Altermatt,
P.P., “A MOS Capacitor Surface
Passivation Structure for Peri-
pheral Regions of High Efficiency
Silicon Solar Cells”, Tech. Digest,
11th International Photovoltaic
Science and Engineering Con-
ference, Sapporo, September,
1999, pp. 339-340.
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT
� S28
Energy Technologies, Pacific Science
Congress, Sydney, July, 1999 pp. 3-10
(ISBN 0 7334 0584 3).
Green, M.A., “Photovoltaics:
Moving From the Outback to the
City”, Solar Progress, Vol. 20, pp. 3-
5, September, 1999.
Green, M.A., J. Zhao, A. Wang and
S.R. Wenham, “Progress and
Outlook for High Efficiency
Crystalline Silicon Solar Cells”, Tech.
Digest, 11th International Photo-
voltaic Science and Engineering
Conference, Sapporo City, Sept-
ember, 1999, pp. 21-24.
Green, M.A., “High Efficiency
Silicon Solar Cells”, B. Courtois, S.
Demidenko (Eds.), Proceedings,
SPIE International Society for
Optical Engineering, ISBN 0-8194-
3494-9, Gold Coast, 27-29 October,
1999, pp. 69-81.
Green, M.A., “Solar Cells and
Renewable Energy”, in Trends in
Materials Science and technology, F.
Bekber, N. Chien, J. Franse, T. Hien,
N. Hien and N. Thesy (Eds.), Hanoi
National University 1999 Publishing
House, ISBN 90-5776-033-9, Pro-
ceedings of the Third International
Workshop on Materials Science,
Hanoi, Vietnam, November, 1999,
pp. 1-6.
Green, M.A. and Wenham, S.R.,
“Photovoltaics for the New Mill-
ennium”, Conf. Record, Australian
Institute of Energy National
Conference, Melbourne, November,
1999, pp. 44-52.
Green, M.A., “Photovoltaics -
Recent Developments”, ANZSES
Solar 99, Geelong, December, 1999.
Keevers, M.J., “Fabrication and
Characterisation of Parallel Multi-
junction Thin Film Silicon Solar
Cells”, Technical Digest, 11th
International Photovoltaic Science
and Engineering Conference,
Sapporo, Japan, Sep. 1999, p. 933.
Nast, O., Brehmer, Pritchard, S.,
Puzzer, T., Aberle, A.G. and
Wenham, S.R., “Aluminum Induced
Crystallisation of Silicon on Glass
for Thin-Film Solar Cells”,
Technical Digest, 11th International
Photovoltaic Science and Engin-
eering Conference, Sapporo, Japan,
Sep. 1999, pp. 727-728.
Neuhaus, D.H., Altermatt, P.P. and
Aberle, A.G., “Determination of the
Density of States in Heavily Doped
Regions of Silicon Solar Cells”,
Technical Digest, 11th International
Photovoltaic Science and Engin-
eering Conference, Sapporo, Japan,
Sep. 1999, pp. 645-646.
Outhred, H. and Watt, M.,
“Prospects for Renewable Energy
in the Restructured Australian
Electricity Industry”, World Re-
newable Energy Congress, 10-13
February 1999, Perth, WA.
Saitoh, T., Wang, X., Hashigami,
H., Abe, T., Igarashi, T., Glunz, S.,
Wettling, W., Ebong, A., Damiani,
B.M., Rohatgi, A., Yamasaki, I.,
Nunoi, T., Sawai, H., Ohtuka, H.,
Yazawa, Y., Warbisako, T. Zhao, J.
and Green, M.A., M.A., “Light
Degradation and Control of Low-
Resistivity CZ-Si Solar Cells - An
International Joint Research”,
Tech. Digest, 11th International
Photovoltaic Science and Engin-
eering Conference, Sapporo,
September, 1999, pp. 553-556.
Schumacher, J.J., Altermatt, P.P.,
Heiser, G., and Aberle, A.G.,
“Application of a New Bandgap
Narrowing Model to the Numerical
Simulation of Saturation Current
Densities of Phosphorus Doped
Silicon Emitters”, Technical
Digest, 11th International
Photovoltaic Science and
Engineering Conference, Sapporo,
Japan, Sep. 1999, pp. 291-292.
Vogl, B., Slade, A.M., Pritchard, S.C.,
Gross, M. and Honsberg, C.B., “The
Use of Silicon Nitride in Buried
Contact Solar Cells”, Tech. Digest, 11th
International Photovoltaic Science and
Engineering Confernce, Sapporo,
Japan, September, 1999, pp. 585-586.
Watt, M. and Outhred, H.,
“Australian and International
Renewable Energy Policy Ini-
tiatives”, World Renewable Energy
Congress, 10-13 February, 1999,
Perth, WA.
Watt, M. and Outhred, H., “Imple-
menting the Renewable Energy
Target”, Outlook 99, ABARE
Conference, 17-18 March, 1999,
Canberra.
Watt, M. and Outhred, H., “Review
of Policy Options for the Australian
Renewable Energy Industry”, Solar
99, 37th ANZSES Conference,
Geelong, Vic, 1-3 Dec, 1999.
Wenham, S.R., Zhao, J., Dai, X.
and Green, M.A., “Surface
Passivation in High Efficiency
Silicon Solar Cells”, Tech. Digest,
11th International Photovoltaic
Science and Engineering Con-
ference, Sapporo, September,
1999, pp. 577-578.
Wenham S.R., Honsberg, C.B.,
Cotter, J., Largent, R., Aberle, A.,
Spooner, T. and Green, M.A.,
“Opportunities Arising Through
Rapid Growth of the Photovoltaic
Industry”, Tech. Digest, 11th
International Photovoltaic Science
Photovoltaics
Special Research Centre
1999 Activities
Photovoltaics
Special Research Centre
1999 Activities
PV3 �
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE
Table of ContentsTable of Contents
T A B L E O F C O N T E N T S
Staff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PV4
Facilities and Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PV6
PPhhoottoovvoollttaaiiccss RReesseeaarrcchh LLaabboorraattoorryy .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV66
DDeevviiccee CChhaarraacctteerriizzaattiioonn AArreeaa .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV77
PPoowweerr EElleeccttrroonniiccss LLaabboorraattoorryy .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV77
LLiittttllee BBaayy FFaacciilliittyy .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV77
Research Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PV8
HHiigghh EEffffiicciieennccyy CCeellll GGrroouupp .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV88
EEffffiicciieennccyy IImmpprroovveemmeenntt ooff PPEERRLL CCeellllss .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV88
BBuurriieedd CCoonnttaacctt RReesseeaarrcchh RReeppoorrtt .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV1122
TThhiinn-FFiillmm GGrroouupp .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV1155
TThheeoorryy GGrroouupp .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV2200
RReenneewwaabbllee EEnneerrggyy PPoolliiccyy aanndd PPllaannnniinngg .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV2255
DDeessiiggnn AAssssiissttaannccee DDiivviissiioonn .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV2266
GGrroooovvee DDiiffffuussiioonn .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV2277
PV5 �
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE
� PV4
Stuart Wenham, BE, BSc, PhD (UNSW),
FTS, SNEE (also Head, Centre for
Photovoltaic Engineering)
Business & Technology Manager
Mark D. Silver, BE (UNSW), GMQ
(AGSM)
DDeessiiggnn AAssssiissttaannccee DDiivviissiioonnMMaannaaggeerr// EExxtteerrnnaall RReellaattiioonnssMMaannaaggeerr
Robert Largent, AS (USA)
AAddmmiinniissttrraattiivvee OOffffiicceeMMaannaaggeerr
Lisa Cahill
CCeennttrree CClleerrkkss
Jenny Hansen
Julie Kwan
Jenny Noble, BA (Hons) (UNSW) (P/T)
Anna Votsis (P/T) (to 6/99)
PPrroojjeecctt aanndd SSeenniioorr PPrroojjeecctt SScciieennttiissttss
Ted D. Spooner, BE, ME (UNSW)
Aihua Wang, BE, PhD (UNSW)
RReesseeaarrcchh FFeelllloowwss aanndd RReesseeaarrcchh AAssssoocciiaatteess
Pietro P. Altermatt, Dipl.-Phys., PhD
(Konstanz)
Patrick Campbell, BSc, BE, PhD
(UNSW)
Richard Corkish, BE (RMIT), PhD
(UNSW)
Nils Harder, Dipl.-Phys. (Leipzig)
(since 6/99)
Mark J. Keevers, BSc, PhD (UNSW)
Daniel Krcho, RNDr (Bratislava)
Ramakant Kumar, PhD, (India)
(5/99 to 7/99)
Hamid R. Mehrvarz, PhD (UNSW)
(to 4/99)
Oliver Nast, Dipl.-Phys. (TU, Berlin)
(to 11/99)
Tom Puzzer, BSc, PhD (UNSW) (P/T)
VViissiittiinngg SSttuuddeennttss
Martin Boettcher (Germany) (to 12/99)
Christian Haase (Germany) (to 12/99)
Marco Lammer (Germany) (to 4/99)
Jurgen Schumacher (Germany) (to 6/99)
SSppeecciiaall PPrroojjeeccttss
Brian Grems (P/T) (to 6/99)
Justin Lucas, BA (Hons) (Syd), PhD
(UNSW), (P/T to 11/99)
StaffStaffDDiirreeccttoorrss
Director
Martin A. Green, BE, MEngSc (Qld.), PhD
(McMaster), FAA, FTS, FIEEE, FIEAust. (to
12/99)
Director (High Efficiency)
Jianhua Zhao, ME, PhD (UNSW), MIEEE
(from 1/00)
Director (Buried Contact)
Christiana B. Honsberg, BEE, MSc, PhD
(Delaware) (from 1/00)
Director (Thin Film)
Armin G. Aberle, BSc, MSc, PhD
(Freiburg), Dr Habil (Hannover) MIEEE,
MDPG (from 1/00)
Associate Director (Systems)
Hugh R. Outhred, BSc, BE, PhD (Syd.),
AMIEE, MIEEE, FIEAust.
AAffffiilliiaatteedd AAccaaddeemmiicc SSttaaffff
Jeffrey E. Cotter, BEE, MSc, PhD
(Delaware)
Gernot Heiser, BSc (Freiburg), MSc
(Brock), PhD (ETH Zurich), SMIEEE,
MACM
John Kaye, BE, MEngSc (Melb.), PhD
(Calif.), MIEEE
Muriel E. Watt, BSc (UNE), PhD
(Murdoch)
S T A F F
AIHUA WANG PREPARING WAFERS FOR EMITTER DIFFUSION.
MARTIN BRAUHART AND MARK
SILVER DISCUSS LABORATORY
REFURBISHMENT PLANS.
JENNY HANSEN, ASSISTANT
TO CENTRE DIRECTOR,
MARTIN GREEN
NNoonn-AAwwaarrdd PPrrooffeessssiioonnaallPPrraaccttiiccuumm SSttuuddeenntt
Manfred Fahr (Efflingen)
LLaabboorraattoorryy aanndd RReesseeaarrcchh SSttaaffff
Professional Officers and
Research Assistants:
Robert Bardos, BSc (Hons) (Melbourne)
Travis Basevi, BE (UNSW) (P/T)
Gordon Bates, BA Ind.Des. (UTS)
(on leave 3/99 to 3/00)
Martin Brauhart, BE (UNSW)
Mark Gross, BSc (Syd), PhD (Syd)
(to 9/99)
Bryce Richards, BSc (Wellington),
MEngSc (UNSW) (P/T)
Lawrence Soria, Assoc.Dip.Comp.Appl.
(Wollongong)
Brendon Vandenberg, BE (Elec)
(UNSW) (P/T)
Bernhard Vogl, BE (Regensburg) (P/T)
Zhu S. Yang, BSc (China)
Technical and Senior
Technical Officers
Tim Seary
Stephen Sleijpen (P/T)
Guang C. Zhang, BE, ME (China)
Laboratory Assistant:
Anja Aberle (Germany) (to 9/99)
HHiigghheerr DDeeggrreeee SSttuuddeennttss
Masters
David Fuertas Marróóón, BSc (Madrid)
Faruque Hossain, BSc, MSc (Dhaka)
Attachai Uerananantasum, BE (Thailand)
Bernhard Vogl, BE (Regensburg)
Johnny Wu, BE, BSc (Queensland)
Doctoral
Matt Boreland, BSc (UNSW) (to 8/99)
Stephen Bremner, BSc (UNSW)
Donald. Clugston, Bsc (Syd)
Didier Debuf, BE, ME (UNSW)
Susie Ghaemi, BE (UNSW) (to 8/99)
Linda Koschier, BE (UNSW)
Daniel Krcho, RNDr (Bratislava)
Keith McIntosh, BSc (Sydney)
Bradley O'Mara, BSc (Oregon IT)
Dirk- Holger Neuhaus, Dipl.-Phys.
(Hannover)
Stephen Pritchard, BA, BE (UNSW)
Dorothy P. Remmer, BAppSc (UBC)
Bryce Richards, BSc (Wellington),
MEngSc (UNSW)
Nicholas Shaw, BE (UNSW)
Alexander M. Slade, BSc (Monash)
Ting Zhang, Electronics Eng. (China)
MARK KEEVERS AND CHRISTIANA
HONSBERG MEASURING THE SPEC-
TRAL RESPONSE OF A SOLAR CELL.
LINDA KOSCHIER WITH A BATCH OF 4 INCH
FLOAT ZONE SILICON WAFERS.
PV7 �
NT based WWW server, one NT
Intranet Server, one Unix workstation
and one Unix computer and WWW
server, support the device laboratory,
the simulation and the Centre's
administrative activities. Another 15
PCs are dedicated for the computer
control of laboratory equipment.
The device laboratories, Character-
isation Area and adjacent facilities
operate 24 hours per day, 365 days per
year and are developed and main-
tained by the Laboratory Dev-
elopment and Operations Team. In
1999, the team, under the leadership
of Mark Silver, comprised 4 full time
and 5 part time employees, which
include electrical and industrial design
engineers and technicians, a physicist,
computer and network manager, and
administrative staff.
Construction work on a $0.5M refur-
bishment of key laboratory safety
infrastructure such as exhaust and
fume cupboards commenced in April
1999 and is due for completion
around May 2000.
Device Character-isation AreaSpace in the basement of the
Electrical Engineering Building was
made available to the Centre by the
University in 1995. The space contains
a reception area, seminar room,
library, offices for Centre staff inter-
acting with the public and industry,
including the Business & Technology
Manager and Design Assistance
Division Manager, computer worksta-
tions for the device modelling activi-
ties of the Centre, and the Device
Characterization Area.
The Device Characterization Area of
60m2 houses characterization equip-
ment including “Dark Star”, the
Centre's station for temperature con-
trolled dark current-voltage measure-
ments, the Centre's Fourier Transform
Infrared Spectroscopy system, Admit-
tance Spectroscopy system, Ellips-
ometer, photoconductance decay
equipment, infrared microscope and
equipment for spectral response and
related optical measurements.
Power ElectronicsLaboratoryThis m2 laboratory, within the School
of Electrical Engineering, is equipped
with a range of power supplies for
heavy current testing of DC-DC con-
verters and inverters including a 60 V
battery bank for remote area power
supply testing. A range of test equip-
ment is available including: high fre-
quency oscilloscopes; true RMS
meters up to 2 MHz response; current
probes up to 1000 A and all the usual
small metering equipment. The labo-
ratory also has a number of micro-
processor/microcontroller develop-
ment systems which include TMS
320C25, and 80C196 systems which
are particularly suited to power elec-
tronic applications. IBM-PC compati-
bles provide analysis software and
printed circuit design and plotting sys-
tems. The laboratory also has access
to programming facilities for a large
range of programmable logic arrays.
Little Bay Facility The Little Bay Solar Energy Research
Facility (approximately 10 minutes
drive from the main University cam-
pus) has been operating a grid con-
nected PV systems for over five years.
The initial installation at the facility
included a 3.8 kW array, battery sys-
tems and inverter connected to the
local grid. Currently, we have 3.8 kW
of BP and Solarex crystalline silicon
arrays and a further 1 kW of Canon
amorphous silicon array. These arrays
are patchable to a large range of
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE
� PV6
atory was integrated into the
Photovoltaics Research Laboratory
complex.
The Photovoltaics Special Research
Centre also owns equipment within,
and has access to, the new Semi-
conductor Nanofabrication Facility
(SNF). This is a joint facility shared by
Physics and Electrical Engineering
and houses a microelectronics labora-
tory and a nanofabrication laboratory
for e-beam lithography.
Additional equipment is available on
the University campus, which is com-
monly used for cell work. Included in
this category are electron micro-
scopes, X-ray diffraction, surface
analysis and photoluminescence
equipment.
A computer network of 54 PCs, one
Novell Server, one NT Server, one
Facilities & Structures
PhotovoltaicsResearchLaboratoryThe Centre boasts the largest and
most sophisticated bulk silicon solar
cell research facility in Australia.
Laboratory space of 480 m2 is located
on three floors of the School of
Electrical Engineering Building and is
serviced with filtered and conditioned
air, appropriate cooling water, pro-
cessing gas, de-ionized water supply,
chemical fume cupboards and
exhausts. There is an additional area of
over 450m2 immediately adjacent to
the laboratories for the accommoda-
tion of staff, research students and
laboratory support facilities. Off site
areas totalling 200m2 are used for the
storage of chemicals and equipment
spare parts.
The laboratory is furnished with a
range of processing and characterisa-
tion equipment including 37 diffusion
furnaces, 6 vacuum evaporation depo-
sition systems, 3 laser scribing ma-
chines, ellipsometer, microwave carrier
lifetime system, rapid thermal anneal-
er, four point sheet resistivity probe,
quartz tube washer, silver, nickel and
copper plating units, infrared and visi-
ble wavelength microscopes, 3 wafer
mask aligners, spin on diffusion sys-
tem, automated photoresist dual track
coater, photoresist spinner, reactive
ion etcher, plasma enhanced chemical
vapour deposition system, glass sur-
face patterning press, TiO2 spray dep-
osition system, electron beam and
sputter deposition systems, and a labo-
ratory system control and data acquisi-
tion monitoring system. In August
1997 the Plasma Processing Labor-
Facilities & Structures
F A C I L I T I E S A N D S T R U C T U R E
FIGURE PV1: LOCATION MAP
FIGURE PV2: LAYOUT OF THE CENTRE WITHIN
THE ELECTRICAL ENGINEERING BUILDING
FIGURE PV3: LITTLE
BAY TRACKING ARRAYS.
series-parallel configurations and are
used for evaluating a variety of systems
under actual operating conditions.
All the systems are being monitored by
an extensive data acquisition system
which logs environmental and electrical
conditions of the systems under test.
A single axis tracking module test facil-
ity is also installed (see Figure PV3).
Each module is connected to an elec-
tronic load which enables a complete
current/voltage characteristic to be
obtained. A data acquisition computer
system controls the electronic loads
and logs environmental conditions,
module temperatures and electrical
characteristics of the modules under
test. The tracking system may be fixed
in orientation or tracked to investigate
module performance under both
conditions.
A range of other test equipment is
available including a Voltec PM3000A
harmonic analyser for investigating
quality of supply issues for both RAPS
and grid connected systems and a high
speed data acquisition system for inves-
tigating protection issues related to grid
connected systems.
The Centre's four major work areas are the Photovoltaics
Research Laboratory, the Device Characterization Area, the
Power Electronics Laboratory and the new Undergraduate
Teaching Laboratory. Systems work is also undertaken at
the Little Bay Research Facility.
PV9 �
cells in the module. This shingled
module encapsulation method com-
pletely eliminated the busbar shading
and busbar resistance loss. Two mod-
ules with such shingle encapsulation
method had demonstrated world
record module efficiency of 22.7%.
Using these PERL cells, Honda
Dream won the 1996 World Solar
Challenge with an astonishing aver-
age speed of 90 km/hr over the
3010 km race course.
Figure PV5 shows the history of
the efficiency evolution for silicon
solar cells. The Centre has made
major contributions to the silicon
solar cell efficiency evolution in the
last one and half decades. Table
PV1 lists the performance of the
most recent record breaking
PERL cell. One major improve-
ment came from the improved
short-circuit current densities of
these cells, helped by the reduced
cell current density. The fill fac-
tor of the cells was also signifi-
cantly improved without the
need for the previous double
metal plating technique.
RReeccoorrdd PPeerrffoorrmmaannccee PPEERRTTCCeellllss oonn MMCCZZ SSuubbssttrraatteess
Solar cells made on moderately to
heavily doped CZ(B) silicon
substrates normally have shown
a degradation problem and gen-
erally poorer cell performance.
To avoid such problems, high
efficiency cells have been fabri-
cated on MCZ(B) (boron
doped magnetically-confined
Czochralski grown), CZ(Ga),
and FZ(B) (boron doped float
zone) substrates. All these sub-
strates were supplied by Shin-
Etsu Handotai Co, Japan,
(SEH). Many of these SEH
materials have a reasonably high
resistivity from 1 �-cm to 5 �-
cm. To reduce the series resist-
ance of these cells, a PERT
(passivated emitter, rear totally-
diffused) cell structure was
developed, which is shown in
Figure PV6. In the experiments,
it was found that the PERT cells
metal shading loss of the picture
frame cell design. The recently
installed planetary motion vacu-
um coating system has con-
tributed to an improved unifor-
mity of the antireflection coating
layers, which also is thought to
have contributed to improved
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS
� PV8
efficiency, which is the highest ever
reported efficiency for a non-FZ
silicon solar cell.
EfficiencyImprovement ofPERL CellsFigure PV4 shows the high efficien-
cy PERL cell structure. In 1997, the
PERL cells were redesigned into a
picture frame metallisation layout to
more accurately define the illuminat-
ed area of the cell. This approach
also reduces the metallisation shad-
ing loss and metal resistance loss.
This new design quickly demonstrat-
ed improved AM1.5 efficiency for
silicon cells of 24.5% in 1998. This
efficiency record has been further
improved to 24.7% in 1999.
The picture frame cell design has the
cell centre illuminated area surround-
ed by a wide metal busbar. The fin-
gers perpendicular to the busbars are
designed to run into the centre of
this illuminated area. The efficiency is
based on the illuminated area. This
efficiency is known as the designated
illumination area efficiency. The pic-
ture frame busbar allows the cell illu-
minated area to be exactly defined to
eliminate any possible misalignment
of the aperture mask to cell periph-
eral regions during cell testing. This
picture frame design also has a
reduced metal finger length. This
allows these fingers to be made nar-
rower to reduce their shading loss,
while still allowing sufficient finger
metal to improve the cell fill factor.
The relevance of a designated illumi-
nation area efficiency was verified
when the Centre produced 20,000
large area PERL cells for the World
Solar Challenge solar car race in
Research ReportsResearch ReportsHigh EfficiencyCell Group
Senior Project Scientist:
Dr Jianhua Zhao (project leader)
University Staff:
Professor Martin Green
Professor Stuart Wenham
Project Scientist:
Dr Aihua Wang
Research Fellow
Pietro Altermatt
Graduate Student:
David Fuertes Marrón (Masters)
Two of the major achievements of
the high efficiency cell group in
1999 were improving PERL cell
efficiencies and the fabrication of
high efficiency cells on non-FZ sil-
icon substrates.
One of the major objectives in
1999 for the high efficiency group
was to further improve the effi-
ciency of PERL (passivated emit-
ter, rear locally-diffused) cells. This
work has demonstrated a 24.7%
energy conversion efficiency for a
cell fabricated on a float-zone (FZ)
substrate, which is the highest ever
reported efficiency for a silicon
solar cell.
Another major objective was to
fabricate high efficiency cells on
non-FZ MCZ (magnetically-con-
fined Czochralski growth), CZ(B)
(boron doped Czochralski) and
CZ(Ga) (gallium doped
Czochralski) substrates. These
materials were supplied by Shin-
Etsu Handotai Co. (SEH), Japan
under a collaboration program.
One of these MCZ cells demon-
strated 24.5% energy conversion
R E S E A R C H R E P O R T S
FIGURE PV4: PASSIVATED EMITTER, REAR LOCALLY-DIFFUSED
(PERL) CELL WITH DOUBLE LAYER ANTIREFLECTION COATING.
FIGURE PV5: EFFICIENCY
EVOLUTION FOR SILICON
SOLAR CELLS.
TABLE PV1: THE PERFORMANCE OF THE RECORD PERL CELL WHICH
WAS TESTED AT SANDIA NATIONAL LABORATORIES, UNDER THE
STANDARD 100 MW/CM2 AM1.5 GLOBAL SPECTRUM AT 25�C.
Cell ID Voc Jsc FF Eff
(mV) (mA/cm2) (%) (%)
Wh20-2b 706 42.2 82.8 24.7
FIGURE PV6: PASSIVATED EMITTER, REAR
TOTALLY-DIFFUSED (PERT) CELL STRUCTURE.
TABLE PV2: THE PERFORMANCE OF THE PERT CELL ON A MCZ
SUBSTRATE, ALSO WAS TESTED AT SANDIA NATIONAL LABORATORIES,
UNDER THE STANDARD 100 MW/CM2 AM1.5 GLOBAL SPECTRUM AT 25�C.
Cell ID Voc Jsc FF Eff
(mV) (mA/cm2) (%) (%)
Ws9-4b 704 41.6 83.5 24.5
1996. Those cells had been designed
with a large busbar area, with the bus-
bar shaded under the next row of
PV11 �
MMOOSS PPeerriipphheerraall PPaassssiivvaattiioonn SSttrruuccttuurree
A MOS (Metal Oxide Semi-
conductor) capacitor structure,
as shown in Figure PV8, has
been investigated to passivate
the peripheral regions for high
efficiency silicon solar cells.
Figure PV8 shows the peripher-
al loss mechanisms in a high
efficiency silicon PERL solar
cell, namely: (a) light generated
carriers diffuse into the periph-
eral region; (b) oblique light
passes into the peripheral
region. The peripheral loss is
enhanced by the fact that the
surface recombination in the
shaded dark peripheral region of
the cell is considerably higher
than that in the illuminated
emitter area, as previous
research has concluded.
When a bias voltage, Vg, as
shown in Figure PV8, is applied
onto the peripheral MOS capac-
itor, it changes the silicon sur-
face status from inversion to
depletion and even to accumula-
tion. These changed surface
MMeeaassuurreemmeennttss ooff tthhee DDooppaanntt DDeennssiittyy
The doping level of the wafers
used for the fabrication of solar
cells is usually obtained from
resistivity measurements, using
an established resistivity/dopant
density relationship. This method
fails in new materials, where no
such relationship has been
established (as for magnetic
Czochralski silicon), or to mate-
rials where such a relationship is
not reproducible due to varia-
tions in grain size etc. Instead,
the doping level in the base may
be determined in fabricated cells
using capacitance-voltage (C-V)
measurements. However, most
theories used for the data evalu-
ation of C-V measurements are
based on the “high-low abrupt
junction” structure, whereas the
PERL cells have medium doped
emitters with a Gaussian dopant
profile. In order to clarify which
data evaluation procedure can
be applied to PERL cells, C-V
curves were simulated with the
software Dessis. The simulation
results were compared with our
measurements of PERL cells
whose dopant profiles are
known. An excellent agreement
was found between our numeri-
cal simulation and the experi-
ment. If analytical data evalua-
tion schemes are applied, the
theory of Hilibrand and Gold
yields the most precise results
among various commonly used
methods. This is so because
Hilibrand and Gold made no
restrictive assumptions on the
location of the edge of the
depletion region.
conditions considerably affect
the recombination rate at the sil-
icon surface, and hence modu-
late the cell performance. It was
found that for negative gate
bias, the short-circuit current
density decreases and the fill
factor increases, while the open-
circuit voltage generally stays
constant. This effect gives a
small overall increase in cell effi-
ciency for negative gate bias
voltage, since the change rate in
fill factor is slightly stronger
than that in short-circuit current
density.
This work concluded that a very
weak surface inversion channel
exits at the silicon surface under
the MOS capacitor. However, it
is believed that this channel can
be cut off by a special designed
boron diffused surface protec-
tion ring, and the efficiency
improvements might then be
then increased to 1% and 2%
relative for 4 cm² and 1 cm²
PERL cells respectively. These
areas will be further investigated
in the future.
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS
� PV10
nation or a period of storage.
Hence, these substrates provide
a solution to the degradation
problem commonly occurring in
CZ(B) silicon substrates. The
work on this topic was awarded
a Best Paper Award at the
11th International Photovoltaic
Science and Engineering Con-
ference (PVSEC-11), Japan, in
September, 1999. A separate
Special Paper Award was also
received for collaborative work
in this area with the Fraunhofer
Institute for Solar Energy Sys-
tems and the Tokyo University
of Agriculture and Technology.
on SEH MCZ substrates have
given open-circuit voltages as
high as standard PERL cells on
Wacker FZ wafers. They also
gave very high cell efficiencies.
A total rear boron diffusion in
this PERT structure appears to
improve the surface passivation
quality of MCZ(B) and some
FZ(B) substrates. Hence, higher
open-circuit voltages were
observed for these PERT cells
than PERL cells for these SEH
MCZ wafers. It is also believed
that these MCZ(B) and other
SEH materials have consider-
ably improved material qualities
under SEH's current effort to
develop high quality substrates
particularly for photovoltaic
applications. This research has
widened our material selection
for high efficiency silicon cells.
Table PV2 shows the perform-
ance of the best PERT cell on a
SEH MCZ substrate. This cell
demonstrated an energy conver-
sion efficiency of 24.5%, which
is the highest energy conversion
efficiency ever reported by a sil-
icon cell made on a non-FZ
substrate. The PERT cell struc-
ture has demonstrated a remark-
able 83.5% fill factor from a 4.8
�-cm resistivity substrate, as a
result of the total rear boron
diffusion. This total rear diffu-
sion has also improved the rear
surface passivation and hence
resulted in high cell open-circuit
voltages. PERT cell features
have also been combined with
CZ(Ga) substrates which has
given an open-circuit voltage of
676 mV.
Also, all the PERT and PERL
cells made on MCZ(B) and
CZ(Ga) substrates have shown
stable performances after illumi-
in a 90-degree different direc-
tion. This enables all the light to
be internally reflected back into
the cell after the first double
pass. These light trapping
schemes have shown improved
long wavelength responses from
the cells, although no direct effi-
ciency improvement has been
observed yet. However, such
light trapping schemes are
expected to improve the effi-
ciency for cells on thinner sub-
strates such as in TPV cells and
concentrator cells, where light
trapping performance is more
critical.
R E S E A R C H R E P O R T S
FIGURE PV7: TWO NEW LIGHT TRAPPING STRUCTURES:
(A) BI-DIMENSIONAL SKEW, (B) QUILTWORK PATTERN.
FIGURE PV8: THE PERIPHERAL LOSS MECHANISMS IN A HIGH
EFFICIENCY SILICON PERL SOLAR CELL ARE: (A) LIGHT GENERATED
CARRIERS DIFFUSE INTO THE PERIPHERAL REGION; (B) OBLIQUE LIGHT
PASSES INTO THE PERIPHERAL REGION. APPLYING A GATE VOLTAGE,
VG, CAN CONSIDERABLE CHANGE THE SURFACE RECOMBINATION
VELOCITY IN THE DARK PERIPHERAL AREA.
NNoovveell LLiigghhtt TTrraappppiinngg DDeessiiggnnss
Two new light trapping schemes
have recently been developed at
UNSW. Figure PV7 shows these
structures as (a) bi-dimensional
skew and (b) quiltwork pattern.
The bi-dimensional skew struc-
ture results in more randomised
light passes by using two differ-
ent pyramid sizes to give con-
trolled offsets. The quiltwork
pattern ensures all the rear sur-
face reflected light returns to a
front area with grooves arranged
Research has also been conduct-
ed to use reactive ion etching to
fabricate deeper inverted pyra-
mid structures. With higher
slope in these deep inverted pyr-
amids, the light can enter the cell
surface with a larger entering
angle, which will allow the
light to travel and to be absorb-
ed closer to the surface
emitter. The high pyramid slope
will also make incident light
bounce more than 3 times on the
pyramid surfaces, to further
reduce the surface reflection.
(A) (B)
PV13 �
cells using a photolithographically
defined rear surface have achieved
open circuit voltages of 695 mV.
Consequently, the key goal in the high
efficiency buried contact solar cell
program is to develop new solar cell
structures with improved rear surfaces
and higher efficiencies. In 1999, the
high efficiency buried contact research
team focused on developing an analy-
sis technique to determine the pres-
ence and relative magnitudes of
recombination in solar cells (particu-
larly for floating junction passivation),
the development of boron back sur-
face fields and the development of a
thyristor solar cell.
Floating junction passivation has
demonstrated the ability to provide
very good rear surface passivation,
and buried contact solar cells using
Furthermore, a solar cell with a boron
BSF can easily be bifacial. An addi-
tional advantage of using boron BSF
passivation is that the process is very
similar to the commercial standard
buried contact solar cell, which has
been demonstrated have to lower
$/Wp cost than conventional com-
mercial solar cells.
High experimental open-circuit volt-
ages on lightly doped material indicate
the low effective surface recombina-
tion velocities achieved with a boron
BSF. For example, buried contact solar
cells on 10 �cm material have reached
645 mV, compared to 595 mV for an
alloyed Al-Si rear. These results are the
highest buried contact voltages
achieved on such high resistivity sub-
strates. In addition, the wafers main-
tained high short circuit currents and
suffered no minority carrier lifetime
degradation even with boron diffu-
sions as heavy as 7 �/�. SEM pho-
tographs in Figure PV12 show the
types of recombination mechanisms.
Of particular importance to high effi-
ciency solar cells is the identification
and analysis of a parasitic shunting
mechanism that acts like an injection-
level dependent rear surface recombi-
nation velocity. For example, Figure
PV11 shows an ideality factor curve,
from which the presence and magni-
tude of the parasitic shunt resistance
can be determined. This technique is
particularly useful for floating junction
devices, in which it is difficult to char-
acterise and analyse this resistance
using other techniques. Using the new
technique, lumped parameter values
for a parasitic shunt, can be quickly
determined for a broad range of float-
ing junction solar cells.
Although floating junctions can pro-
vide excellent surface passivation, the
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVTTIIEESS
� PV12
like continuous-sheet multicrystalline
silicon wafers, continue to appear on
the horizon; and manufacturers are
tending to use a broader variety of
feedstock wafers. Therefore, there is
considerable opportunity to develop
new solar cell processes and device
designs that are well matched to spe-
cific types of silicon wafers - process-
es and designs that enable high effi-
ciency in high-quality, higher-cost
wafers and vice versa (as shown in
Figure PV10). Thus, the BSCS activi-
ties are divided into two main research
areas: the High-Efficiency and
the Simplified Buried Contact solar
cell projects.
HHiigghh EEffffiicciieennccyy BBuurriieedd CCoonnttaaccttSSoollaarr CCeellllss
The many advantages and high effi-
ciency features of the top surface of
the standard buried contact solar cell
allow open circuit voltages close to
700 mV. For example, hybrid BC solar
R E S E A R C H R E P O R T S
FIGURE PV10: DEMONSTRATION OF RANGE OF BURIED CONTACT
(BC) SOLAR CELL STRUCTURES AND TYPES OF WAFERS TO WHICH
THEY ARE SUITED. THE SOLID LINES ARE MODELLING RESULTS AND
THE POINTS REPRESENT EXPERIMENTAL VALUES. THE PURPLE LINE/
POINTS REFERS TO A HIGH EFFICIENCY BURIED CONTACT STRUCTURE,
THE DOUBLE-SIDED BURIED CONTACT SOLAR CELL. THE BLUE LINES AND
POINTS REFER TO THE STANDARD BURIED CONTACT SOLAR CELL AND
THE RED LINE/POINTS ARE RESULTS FOR THE SIMPLIFIED BURIED
CONTACT SOLAR CELL STRUCTURE.
FIGURE PV11: GRAPH SHOWING THE EFFECT OF
VARIOUS RECOMBINATION MECHANISMS
ON THE IDEALITY FACTOR CURVE.
FIGURE PV12: COMBINED SEM
AND EBIC RESULTS COMPARING
BORON DIFFUSED AND AL-ALLOYED
REAR SURFACE ON AN N-TYPE SUB-
STRATE. THE WHITE REGIONS
SHOW THE JUNCTION BETWEEN
THE P-TYPE SUBSTRATE AND
N-TYPE BACK SURFACE FIELD. A)
BORON DIFFUSED BACK SURFACE
FIELD. B) AL-SI ALLOYED BACK
SURFACE FIELD.
Buried ContactResearch ReportUniversity Staff:
Dr Jeffrey Cotter,
Professor Martin Green,
Dr Christiana Honsberg
(project leader),
Professor Stuart Wenham
Research Staff
Dr XiMing Dai, Dr Hamid Mehrvarz
Graduate Students
Linda Koschier (PhD), Keith
McIntosh (PhD), Bryce Richards
(PhD), Stephen Pritchard (PhD)
Alexander Slade (PhD), Bernhard
Vogl (Masters), Attachai
Ueranantasun (MsEngSci), Faruque
Hossain (MsEngSci)
U/graduate students
James Lee, Khairil Anwar
Kamarudin,Wee Chong Tan
Visiting Student
Manfred Fahr
The Buried Contact Solar Cell (BCSC)
group aims to develop new processing
technologies and device designs based
around the laser-groove grid electrode.
The established BCSC technology
continues to enjoy considerable suc-
cess in both the laboratory and the
commercial market. Figure PV9 shows
a recent application of BP-Solarex's
Saturn Modules installed during 1999
at the Sydney Olympic Village. The
Saturn Module is still the highest effi-
ciency, commercially available photo-
voltaic module.
The BCSC group has a broad spec-
trum of research and development
activities that address the evolving
nature of commercial silicon wafers.
Existing commercial silicon wafers
continue toward improved quality and
reduced cost; advances in sawing and
handling are leading to the use of
thinner wafers; new types of wafers,
FIGURE PV9: LIGHT TOWERS
AT THE OLYMPIC STADIUM IN
HOMEBUSH BAY USING BURIED
CONTACT MODULES PRODUCED
BY BP SOLAREX.
floating junction passivation have
achieved open circuit voltages of 687
mV. A key issue in analyzing such high
efficiency devices is the determination
of the presence and relative impact of
recombination mechanisms. Analysis
of the light J-V, dark J-V and Jsc-Voccurves and their second derivatives
(that is the m versus V or ideality fac-
tor curve) gives considerable insight
into the type and severity of several
flexibility inherent in the double-sided
BC solar cell also allows the study and
use of other passivation techniques.
Back surface field (BSF) passivation
using boron diffusion is an additional
option for rear surface passivation.
Boron back-surface-fieldpassivation
may be particularly desirable in situa-
tions where a high reflectivity at the
rear is desired - for example, in thin
wafers that require light trapping.
PV15 �
acteristic of two small pieces of the
same solar cell - one that does and one
that does not contain an area of junc-
tion punch-through. Modifying the
electroless nickel and copper deposi-
tion and sintering conditions has
proved to be successful in forming a
metal contact that has both low con-
tact resistance and minimal junction
punch-through. For example, 9 cm2
solar cells fabricated with a homoge-
neous emitter (at 50 �/sq.) have
exceeded 17% efficiency [Voc =
613 mV, Jsc = 34.8 mA/cm2. (not tex-
tured, SLAR: nr = 2.2), FF = 80.1%]
in commercially available Czochralski
silicon wafers. Stable fill factors over
79%, which is indicative of low con-
tact resistance and the absence of
junction punch-through, are achieved
regularly with the modified metallisa-
tion process. This result compares
favourably to standard BC solar cells
made with the same type of wafer, in
which 16.5% efficiency [Voc =
617 mV, Jsc = 33.4 mA/cm2 (not tex-
tured, SLAR: nr = 1.4), FF = 80.2%]
is regularly achieved.
The SBC team initiated a new project
area in 1999 focused on the develop-
ment of new solar cell fabrication
processes based on spray-hydrolysis
deposited titanium dioxide. Although
thin films of titanium dioxide have
been developed for a variety of pur-
poses, their use within the PV industry
is almost exclusively limited to anti-
reflection coatings. In work that is in
the process of being published, the
team will demonstrate the film's
chemical resistance to most common
wet chemical etches, the selective dep-
osition of it on the surface without
coating inside laser grooves, its suit-
ability as a electroless metal plating
mask, use of it during high-tempera-
ture processing with no contamina-
tion of either wafer or furnace and it's
ability to passivate lightly diffused n-
type emitters to a degree suitable for
� the crystallisation of amor-
phous silicon (a-Si) films on
glass at low temperature (<
600 °C) using metal-induced
crystallisation and the char-
acterisation of the resulting
polycrystalline silicon films,
� the development of a surface
texture method for glass
substrates,
� the investigation of the light
trapping properties of amor-
phous silicon films deposited
on textured glass substrates,
� experimental studies evaluating
the feasibility of the ion-assisted
deposition method for the fabri-
cation of polycrystalline silicon
solar cells on glass, and
� fundamental experimental in-
vestigations of the parallel multi-
junction thin-film silicon solar cell,
a novel device structure recently
conceived at UNSW and present-
ly being commercialised by Pacific
Solar in Sydney.
MMeettaall-iinndduucceedd CCrryyssttaalllliissaattiioonn ooff SSiilliiccoonn
One of the most challenging prob-
lems for the development of poly-
crystalline silicon thin-film solar cells
is the growth of crystalline silicon
on foreign, low-cost and low-tem-
perature substrates. We are investi-
gating aluminum-induced crystalli-
sation (AIC) as an alternative
process to the commonly used
processes such as laser crystallisation
and solid phase crystallisation (SPC).
Using AIC, we have achieved sub-
stantially faster crystal growth than
SPC and crystal grains larger than in
laser crystallised material. The phe-
nomenon of the AIC as studied in
our group is that adjacent aluminum
and amorphous silicon layers
exchange places when heated at a
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS
� PV14
being developed specifically for
Czochralski and multicrystalline
wafers. Solar cell performance in these
types of wafers is primarily limited by
the electrical quality of the wafer itself,
and therefore, there is considerable
scope to simplify the fabrication
process without a loss in performance.
In 1999, the team continued work on
the development of a homogeneous
emitter process that eliminates two of
four high-temperature process steps
from the standard BC process. In
addition, the team introduced two
new initiatives: (1) the expansion of
the capabilities of titanium dioxide
beyond its use as an antireflection
coating, and (2) the development of
novel processes to be used in a low-
cost, rear surface structure, specifically
for thin silicon wafers.
One of the key issues associated with
the use of a homogeneous emitter is
selecting the optimal diffusion profile
that minimises emitter and groove
recombination, that minimises contact
resistance, and that avoids junction
punch-through after contact sintering.
Previous work demonstrated that the
total emitter (emitter and groove) dark
emitter saturation current is
minimised (typically, Joe = 250 fA/cm2)
physical difference between the boron
and aluminum back surface field.
An additional method for surface pas-
sivation of the rear is to use a thyris-
tor-structure solar cell. Figure PV13
shows the schematic of a thyristor
structure solar cell. The thyristor solar
cell uses its multiple junctions for two
purposes. Under illumination, the inci-
dent light and the forward bias of the
top junction ensure that all the junc-
tions are forward biased, thus allowing
the light generated current to pass
through the solar cell while also passi-
vating the rear surface. In the dark, the
thyristor solar cell does not allow cur-
rent flow, and thus each individual
solar cell acts as a blocking diode. Ex-
perimental thyristor solar cells exhibit
higher open-circuit voltages compared
to identical devices with an aluminum
sintered rear surface.
SSiimmpplliiffiieedd BBuurriieedd CCoonnttaacctt ((SSBBCC))SSoollaarr CCeellllss
The SBC team is pursuing a variety of
nov technologies that can potentially
reduce the cost of processing while
retaining the efficiency potential of
laser-grooved front grid electrodes.
The SBC technology is presently
at a sheet resistance of about
50-70 �/sq. for typical surface passi-
vation conditions. Also, the short cir-
cuit current is relatively independent
of the emitter sheet resistance down
to about 40 �/sq.
Work on the homogeneous emitter in
1999 focused on developing the
groove metal deposition and sintering
conditions to minimise contact resist-
ance and to avoid junction punch-
through. The standard nickel/copper
plating and sintering process requires
a heavily diffused groove for low con-
tact resistance and minimal shunting.
While this process results in accept-
ably low contact resistance for lightly
diffused grooves (equivalent to a spe-
cific series resistance of less than 0.2
�-cm2), the resulting electrodes are
shunted by small-area, localised metal-
silicon rectifying junctions, where the
nickel has punched through the emit-
ter to contact the p-type silicon. Figure
PV14 shows the current-voltage char-
R E S E A R C H R E P O R T S
FIGURE PV14: CURRENT- VOLT-
AGE CHARACTERISTICS OF TWO
PIECES CUT FROM A SINGLE
SOLAR CELL. THIS ILLUSTRATES
THE LOCALISED NATURE OF
JUNCTION PUNCH-THROUGH IN
A LIGHTLY DIFFUSED
GROOVE (45 �/�).
Czochralski silicon wafers. The SBC
team also initiated a new project area
in 1999 focused on novel, low-cost,
rear-surface structures for thin silicon
wafers. Staff and students working in
this project area are examining the
suitability of forming an aluminum-
silicon contact in the shape of a grid
electrode using a laser beam to effect
the alloying process, as well as the
development of pigmented diffuse
rear-surface reflectors to enhance the
light trapping of solar cells fabricated
on thin silicon wafers.
Thin-Film GroupUniversity Staff:
Dr Armin Aberle (group leader),
Professor Martin Green,
Professor Stuart Wenham
Research Fellows:
D. Pietro Altermatt,
Dr Patrick Campbell,
Dr Mark Keevers (project leader
parallel multijunction cells),
Dr Ramakant Kumar (05/99 - 07/99),
Dr Tom Puzzer
Graduate students:
Nils-Peter Harder (PhD),
Oliver Nast (PhD; to 11/99),
Dirk-Holger Neuhaus (PhD),
Nicholas Shaw (PhD),
Johnny Wu (Masters)
U/graduate students:
Kah Mun Thong (to 11/99),
Chun Cheong Wong (to 11/99),
Chee Bon Tan (since 07/99)
Visiting Students:
Martin Boettcher (12/99),
Christian Haase (12/99)
The primary aim of the thin-
film group is to develop poly-
crystalline thin-film silicon solar
cells on glass, an approach that
is widely recognised as being a
pathway towards substantially
lowering the cost of solar cells.
In 1999, our main areas of work
have been:
FIGURE PV13: SCHEMATIC OF A THYRISTOR STRUCTURE SOLAR CELL.
PV17 �
grain structure, and (vi) the Al/a-Si
interface. The results of these stud-
ies are presently used to optimise
the crystallisation process. This may
ultimately lead to the realisation of
high-quality poly-Si films on glass
at low temperature that are suitable
for the subsequent fabrication of Si
thin-film solar cells.
FFaabbrriiccaattiioonn ooff aa SSuurrffaacceeTTeexxttuurree ffoorr GGllaassssSSuubbssttrraatteess
Our previous modelling studies have
shown that a silicon thin-film solar cell
conformally deposited on a textured
substrate can provide both very effec-
tive light trapping and very effective
reduction of front surface reflection
losses. We have developed a method
to accurately emboss a surface texture
into glass. The method consists of
heating glass to a workable viscosity
and then pressing a texture into its sur-
face with a textured die. We have been
using a silicon wafer as the die. The sil-
icon wafer is textured with inverted
pyramids (side length 10 �m) and rein-
forced by bonding its rear side to
another silicon wafer. An inert ceram-
ic coating is used to isolate the highly
reactive heated glass surfaces from
supports and the die. We are currently
installing a gimbal joint in the pressing
apparatus to improve the uniformity
of the texture. A scanning electron
micrograph of a pressed glass texture
is shown in Figure PV18.
LLiigghhtt TTrraappppiinnggMMeeaassuurreemmeennttss
The accuracy of current optical
and spectral response methods
used to measure the light trap-
ping properties of a sample are
severely limited by parasitic
effects. We developed a way
around this by measuring the
relative enhancement of the
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS
� PV16
in the range 350 to 525 °C. Thus,
simple and industrially relevant
deposition and processing techniques
are employed.
Figure PV15 shows the effect of
the layer exchange when adjacent
layers of Al and a-Si are annealed
at low temperature. The Al that
segregated to the top of the
structure during the crystallisa-
tion process can be selectively
etched off. The resulting struc-
temperature well below the eutectic
temperature of 577 ºC of the Si/Al
binary system. During the exchange
process, a polycrystalline silicon layer
is formed at the original position of
the Al film. The Al/Si layered struc-
ture is fabricated on glass substrates
(Corning 1737). The Al and a-Si are
deposited by thermal evaporation
and dc magnetron sputtering, respec-
tively. The crystallisation takes place
during a subsequent isothermal
annealing process at a temperature
ture is a continuous polycrys-
talline silicon film on glass. The
crystallographic properties of
these poly-Si films were investi-
gated using Raman spectroscopy,
secondary electron microscopy
(SEM), transmission electron
microscopy and in-situ optical
microscopy.
Figure PV16 shows a comparison
of Raman spectra taken on a crys-
talline Si wafer and a poly-Si layer
formed by AIC at 500 °C. The
close agreement of the two spectra
is an indication of the high crystal-
lographic quality of our polycrys-
talline material.
The structure and size of the grains
of the poly-Si material can be stud-
ied when the Si films are separated
from the glass substrate by means
of chemical etching. This prepara-
tion enables the investigation of
clean and smooth surfaces. Figure
PV17 shows an electron chan-
nelling SEM image of such a poly-
Si film, revealing grain sizes above
10 µm. The electrical properties of
the poly-Si films were investigated
using Hall effect measurements.
According to these experiments,
which were performed in coopera-
tion with the Hahn Meitner
Institute, Berlin, the material is of
p-type character due to high doping
with Al atoms (~2 ��1018 cm-3).
The AIC work conducted in 1999
focused on various process param-
eters that influence the exchange of
the Al and Si layers during the crys-
tallisation, and consequently have
an impact on the final characteris-
tics of the poly-Si film. The param-
eters that seem to have a major
influence on the overall process are
(i) the annealing time, (ii) the layer
thickness ratio, (iii) the temperature,
(iv) the layer sequence, (v) the Al
R E S E A R C H R E P O R T S
FIGURE PV16: RAMAN SPECTRA OF A POLYCRYSTALLINE SAMPLE AND, FOR
COMPARISON, A POLISHED SINGLE CRYSTALLINE SI WAFER. EACH SPEC-
TRUM IS NORMALISED TO ITS MAXIMUM VALUE.
FIGURE PV17: ELECTRON
CHANNELLING SEM
IMAGE OF THE FORMER
POLY-SI/GLASS INTERFACE OF
FULLY CRYSTALLIZED SAMPLES
ANNEALED AT 500 ºC.
FIGURE PV18: SCANNING
ELECTRON MICROGRAPH OF
A GLASS PANE UNIFORMLY
TEXTURED WITH UPRIGHT
PYRAMIDS, FORMED BY PRESSING
A SILICON WAFER COVERED WITH
INVERTED PYRAMIDS ONTO THE
GLASS AT HIGH TEMPERATURE
AND PRESSURE. (PICTURE TAKEN
BY TOM PUZZER)
photoconductance of undoped
hydrogenated amorphous silicon
films deposited on textured and
untextured glass substrates,
respectively. At present we are
investigating the light trapping
properties of 10 �m thick a-Si
films, as for thinner films the
accuracy of this method is
severely reduced due to the para-
sitic surface recombination
effect. We are also developing
suitable surface passivation tech-
niques for a-Si, allowing us to
extend the method to
thinner films.
TThhiinn-FFiillmm SSiilliiccoonn SSoollaarr CCeellllss oonnGGllaassss bbyy IIoonn-AAssssiisstteedd DDeeppoossiittiioonn((IIAADD))
The major aim of the thin-film
approach to solar cells is cost reduc-
tion while maintaining good efficien-
cy. Therefore, it is crucial to develop
processes that are compatible with
FIGURE PV15: CROSS-SECTIONAL FOCUSED ION BEAM MICROGRAPHS
OF THE A-SI/AL/GLASS STRUCTURE: (A) BEFORE ANNEALING; (B) AFTER
ANNEALING FOR 30 MIN AT 500�C; AND (C) SEM MICROGRAPH AFTER
AL ETCHING, EXPOSING THE CONTINUOUS POLY-SI LAYER. NOTE THE
SAMPLES ARE TILTED IN THESE MICROGRAPHS [45� IN (A) AND
(B) AND 20� IN (C)], SO THE SCALES ARE ONLY VALID IN THE HORIZONTAL
DIRECTION. THE SHORT WHITE DOTTED LINE IN (C) IS A GUIDE TO THE EYE.
PV19 �
have efficiencies up to 13 %, with
Voc, Jsc and FF values typically
around 630 mV, 24 mA/cm2 and
78 %, respectively.
The development of a baseline
process for the fabrication of
PMJ test-bed cells opens up a
wealth of opportunities for the
systematic investigation of PMJ
cell performance and its limiting
mechanisms, such as junction
recombination, and the implica-
tions of various cell design and
processing options, particularly
those likely to be of more com-
mercial relevance, such as laser
scribing, laser doping, rapid
thermal processing and electro-
less metal plating.
As a first experimental study of PMJ
cells, we have systematically investigat-
ed the impact of poor material quality
on cell performance using 10 MeV
proton irradiation to controllably
degrade the silicon quality in complet-
ed PMJ cells from its initial “pristine”
state. As Figure PV23 shows, the PMJ
cell clearly exhibits a greater radiation
tolerance than identically processed
single-junction (SJ) cells. This indi-
isolation trenches, with interdigitat-
ed n- and p-type buried contact grids
of about the same depth. Only one
type of multilayer stack has been
avail-able for the project to date. It
consists of n-p-n-p-n epilayers
(17 �m total, doped 1017 cm-3) on a
p+ buffer layer (15 �m thick,
doped 1018 or 1019cm-3) fabricated
on a p+ single-crystal CZ wafer
(630 �m thick, 0.01 �cm).
The processing sequence devel-
oped to fabricate these PMJ test-
bed cells is based on photolithog-
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS
� PV18
talline silicon wafers as substrate,
the company ANTEC in Germany
has already proven that IAD is
capable of providing high-quality
crystalline silicon films. In 1999 we
have started a cooperation with
ANTEC, enabling us to perform
first experimental studies using
ANTEC equipment in Germany.
Figure PV19 shows the main fea-
tures of an IAD system. After the
silicon atoms are ionised, they can
be accelertaed towrds the substrate
using an electric field. This addition-
al energy enables the deposited sili-
con atoms to take over the crys-
talline order of the substrate even at
low temperatures. When using glass
as a substrate, it has to be coated by
a silicon layer that can act as a seed
for the subsequent growth of good
quality polycrystalline silicon. As
discussed above such as seeding
layer has already been developed by
our group using aluminium-induced
crystallisation.
PPaarraalllleell MMuullttiijjuunnccttiioonn TThhiinn-ffiillmm SSiilliiccoonn SSoollaarr CCeellllss
The parallel multijunction (PMJ)
thin-film silicon solar cell, shown in
cheap substrate materials (e.g. stan-
dard glass). The use of standard
glass restricts cell processing to rel-
atively low temperatures of below
about 600° C. For most thin-film
technologies, this restriction leads
to comparatively low material quali-
ty, a drawback that can only be com-
pensated for using specialised cell
structures such as the parallel multi-
junction cell discussed below. In
contrast to this approach (which is
followed by the company Pacific
Solar in Sydney), the thin-film
group at UNSW is aiming at devel-
oping a process for high-quality
Figure PV20, theoretically enables
high efficiency on low-cost, poor-
quality polycrystalline silicon.
Commercialisation of this exciting
new technology is currently being
undertaken by Pacific Solar in
Sydney. Here at UNSW, one research
strand is focussing on a more funda-
mental study of this novel device
structure, with a particular emphasis
on quantifying the impact of materi-
al quality on cell performance.
The initial focus of this work was
the fabrication of PMJ test-bed
devices amenable to systematic
experimental studies of this rather
complex cell structure but still con-
taining the essential features of the
PMJ cell - namely a multilayer stack
of n- and p-type silicon layers, and
buried contact grooves which elec-
trically connect all like-polarity layers
in parallel. The PMJ test-bed cells
fabricated are shown schematically
in Figure PV21. These cells are
made from commercially available
high-temperature CVD epilayers
grown on highly doped single-crys-
tal silicon wafers (rather than the
glass superstrate of Figure PV20.
The cells are 1-cm2 mesa-shape
devices separated by 25 �m deep
R E S E A R C H R E P O R T S
FIGURE PV20: THE PARALLEL MULTIJUNCTION THIN-FILM SILICON CELL,
CONSISTING OF ALTERNATING POLARITY N- AND P-TYPE LAYERS, WITH LIKE-
TYPE LAYERS CONNECTED IN PARALLEL USING A BURIED CONTACT GRID.
FIGURE PV21: SCHEMATICS OF THE ACTUAL PMJ CELLS FABRICATED ON SINGLE-CRYSTAL WAFER
SUBSTRATES FOR THIS MORE FUNDAMENTAL STUDY: (A) CROSS-SECTIONAL VIEW; (B) TOP VIEW.
FIGURE PV22: PARALLEL ELECTRICAL CONNECTION OF LIKE-POLARITY
SILICON LAYERS IS SHOWN IN THESE CROSS-SECTIONAL EBIC/SE
IMAGES OF AN N- AND P-TYPE FINGER IN A PMJ CELL. THE BRIGHT
REGIONS INDICATE THE p-n JUNCTIONS.
(A) (B)
raphy, anisotropic wet etching,
high-temperature oxidations and
diffusions, and evaporated metalli-
sation. Critical to the fabrication of
the present devices is the use of a
thick photoresist required for
adequate coverage of the device's
25 �m deep vertical features.
Evidence for successful parallel
electrical connection of like-polari-
ty layers is clearly shown in the
cross-sectional EBIC/SE (elec-
tron-beam-induced current/sec-
ondary electron) images of Figure
PV22 . The fabricated PMJ cells
FIGURE PV19: SCHEMATIC REP-
RESENTATION OF AN ION-
ASSISTED DEPOSITION (IAD)
SYSTEM FOR THE FABRICATION
OF GOOD-QUALITY POLYCRYS-
TALLINE SILICON FILMS AT LOW
TEMPERATURE (< 600��C).
polycrystalline silicon films on glass
at low temperature (< 600 °C).
One of the silicon growth/deposi-
tion methods that we are investigat-
ing is “ion-assisted deposition”
(IAD). Using elevated temperatures
in the 600 - 800 °C range and crys-
PV21 �
Research Fellows:
Dr Pietro Altermatt
Dr Patrick Campbell
Dr Richard Corkish
Dr Mark Keevers
Graduate Students:
Stephen Bremner (PhD), Didier
Debuf (PhD), David Fuertes Marrón
(Masters), Keith McIntosh (PhD),
Dirk-Holger Neuhaus (PhD),
Nicholas Shaw (PhD)
Undergraduate Students:
Kah Mun Thong (to 11/99),
Kee Meng Wee (to 01/99)
Visiting Students:
Marco Lammer (to 04/99),
Jürgen Schumacher (to 06/99).
EEBBIICC MMooddeelllliinngg
The three-dimensional numerical
electron beam induced current
(EBIC) model used previously to
study grain boundaries in mul-
ticrystalline silicon has been
adapted to simulate the response
to an electron beam scanning
across the edge of a solar cell. The
aim is to determine both bulk and
surface recombination parameters
from experimental scans by com-
parison with comprehensive and
reliable simulations. In the past,
analytical expressions have been
used for this purpose. Those
expressions have, by necessity,
involved more simplifications
than are needed in this work. As a
representative example, Figure
PV25 shows a two-dimensional
section from a three-dimensional
numerical simulation of the inter-
action of a narrow electron beam
with a Si solar cell. For these sim-
ulations the solar cell was rotated
anti-clockwise by 90°, so that the
cell edge faces the incoming elec-
tron beam. The blue region on the
HHeeaavvyy DDooppiinngg EEffffeeccttss iinn SSiilliiccoonn
The introduction of dopants into
the silicon crystal changes its den-
sity of states (DOS). Usually, heav-
ily doped silicon has been mod-
elled using solely the ideal DOS of
undoped silicon, regardless of the
doping level. However, this crude
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVTTIIEESS
� PV20
cates that, in addition to terrestrial
applications, PMJ cells are also well
suited for space applications. The
superior efficiency of the PMJ cells in
heavily defected silicon (lifetimes as
low as 10 ps) is the first experimental
demonstration of their predicted
performance advantage in poor-
quality material.
QQuuaannttuumm WWiirreess iinn SSiilliiccoonn
In addition to the thin-film solar cell
work described above, we are also
investigating new methods of fabri-
cating quantum wires in silicon. Such
wires are a key feature of upcoming
nanoscale semiconductor devices.
Such low-dimensional structures may
also have application to advanced
solar cell designs. As yet, such wires
have only been realised using sophisti-
cated approaches and, in general,
expensive semiconductor materials. In
contrast, in this project we aim at fab-
ricating quantum wires in today's stan-
dard material, silicon, using a striking-
ly simple approach that is compatible
with the mainstream microelectronics
industry. The basic idea of the
Theory Group
University Staff:
Dr Armin Aberle (group leader)
Dr Jeff Cotter
Professor Martin Green
A/Professor Gernot Heiser
Dr Christiana Honsberg
Professor Stuart Wenham
R E S E A R C H R E P O R T S
FIGURE PV25: CALCULATED BULK CARRIER RECOMBINATION RATE
IN A SHORT-CIRCUITED SILICON SOLAR CELL 'ILLUMINATED' FROM
THE SIDE WITH A NARROW ELECTRON BEAM. THE CELL IS ROTATED
ANTI-CLOCKWISE BY 90°, SO THAT THE EMITTER (DARK BLUE
REGION) RUNS VERTICALLY.
FIGURE PV26: CALCULATED SHORT-CIRCUIT CURRENT OF THE
SILICON SOLAR CELL OF FIGURE PV25 AS A FUNCTION OF THE
ELECTRON BEAM DISTANCE FROM THE JUNCTION AND THE SURFACE
RECOMBINATION VELOCITY (SRV) OF THE CELL EDGE. THE BULK
ELECTRON LIFETIME IS THE SAME FOR ALL CURVES (20 NS).
left represents the emitter of the p-
n junction cell. The electron beam
enters the cell 10 �m away from
the junction. Figure PV26 shows
the corresponding short-circuit
current of the solar cell as a
function of the electron beam dis-
tance from the junction and the
surface recombination velocity of
the cell edge.
FIGURE PV23: COMPARISON OF (A) SHORT-CIRCUIT CURRENT AND (B) EFFICIENCY DEGRADATION OF
IDENTICALLY PROCESSED PMJ AND SINGLE-JUNCTION SILICON SOLAR CELLS IRRADIATED WITH 10 MEV
PROTONS. PERL CELL DEGRADATION IS ALSO SHOWN FOR COMPARISON.
(A) (B)
approach is the one-dimensional local-
isation of electrical charges within an
insulator on a silicon wafer by means
of an atomic-resolution microscope.
By creating a sufficiently large charge
density, a quantum wire with unprece-
dented structural fineness can be
induced in the silicon. As insulator we
are using a double-layer stack consist-
ing of an ultra-thin (~1.5 nm) thermal
oxide and a plasma silicon nitride film.
FIGURE PV24: SHOWS A SCHEMATIC REPRESENTATION OF
THE SAMPLES INVESTIGATED IN THIS PROJECT.
PV23 �
theory, while the carrier lifetime
measurements were performed at
the ANU. In the course of this
work, the Auger recombination
rate has also been calculated and
measured under high-injection
conditions, and we found good
agreement with results previously
published by other groups. This
opens up possibilities for develop-
ing a general Auger model, which
will be valid under all relevant
combinations of dopant and injec-
tion densities.
AAddmmiittttaannccee SSppeeccttrroossccooppyy
In this project, we improve the
understanding of the admittance
of various device structures: sin-
gle-crystalline cells and multi- or
poly-crystalline cells, partly made
as thin films. In order to establish
a firm basis, we initially investigat-
ed only the imaginary part of the
admittance (i.e. the capacitance),
because much work has been pub-
lished in this field. We determined
the influence of the Gaussian
emitter profile on the capacitance,
and compared it to the case of an
“abrupt high-low junction”,
which is extensively treated in the
literature. We simulated the admit-
tance with the software Dessis,
where the small-signal AC analysis
was recently implemented and was
still in its test phase. We found
excellent agreement between our
simulations and our measure-
ments. This helps to understand
how the small-signal analysis
needs to be combined with the
boundary conditions of the simu-
lations. We also found that, when
extracting the dopant profile from
C-V measurements, some com-
monly used data evaluation proce-
dures (based on the depletion
region approximation) may lead to
significant errors.
As described above and in last
year's Annual Report, we have
successfully introduced Schenk's
bandgap narrowing model to
device simulation. This model
enables us to simulate highly
doped regions using Fermi sta-
tistics for the free carrier distri-
bution. This is a major concep-
tual improvement because, so
far, the effect of Fermi degener-
acy has only been partly includ-
ed in device modelling by the
“apparent bandgap” concept,
contributing, to significant dis-
crepancies between simulated
and experimental open-circuit
voltages of silicon cells with
highly doped emitters. Schenk's
bandgap narrowing model
enables us to separate degenera-
cy and band shrinkage effects in
the interpretation of saturation
current measurements. This
allows us to derive S values that
are based on a sounder theory.
SSiimmuullaattiioonn ooff PPrroottoonn-IIrrrraaddiiaatteedd SSiilliiccoonn SSoollaarrCCeellllss
One way to understand and
quantify losses induced by crys-
tal defects in thin-film solar cells
is to irradiate monocrystalline
cells with protons in a con-
trolled manner. We irradiated
monocrystalline PERL cells and
simulated their current-voltage
(I-V) curves and quantum effi-
ciency behaviour. We showed
that changes in both the recom-
bination rate and the diffusion
length can be described with the
Shockley-Read-Hall formalism,
using a defect energy level of
Ec - 0.42 eV, corresponding to
the 0/- charge state of the diva-
cancy, in agreement with publi-
cations from IMEC, Belgium.
As expected, we observed that
IInnttrriinnssiicc CCaarrrriieerr DDeennssiittyy
The commonly used value for the
intrinsic carrier density ni of crys-
talline silicon is 1.00 ��1010 cm-3 at
300 K. This value was experimen-
tally determined by A. Sproul and
M. Green in 1990, using specially
designed solar cells. However, more
recent measurements by Misiakos
and Tsamakis gave a slightly lower
ni value of 9.7 ��109 cm-3. We re-
evaluated the measurements of
Sproul and Green, using the device
simulator Dessis and a new quan-
tum-mechanical model for
bandgap narrowing developed by
Andreas Schenk from ETH
Zurich. We found that the experi-
ment by Sproul and Green was
influenced by bandgap narrowing,
despite the low dopant density
(1014 to 1016 cm-3) of their samples.
Our new interpretation provided
an ni value of 9.65 �� 109 cm-3 at
300 K, which is consistent with the
work of Misiakos and Tsamakis on
a lightly doped substrate.
SSuurrffaaccee RReeccoommbbiinnaattiioonn aatt tthhee EEmmiitttteerr SSuurrffaaccee
In contrast to lowly doped surfaces
(e.g., at the rear of PERL cells), the
surface recombination velocity S of
highly doped surfaces (e.g. the sur-
face of the emitter of silicon cells) is
only indirectly accessible. This is so
because S of the emitter surface is
usually extracted from measure-
ments of the emitter saturation cur-
rent, where losses in the emitter bulk
region are included and need to be
subtracted. The losses in the bulk
region of the emitter are not well
understood, as the inconsistencies
among the numerous publications
on this topic indicate. Hence, differ-
ent models for the emitter bulk loss-
es lead to different S values deter-
mined for the emitter surface.
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS
� PV22
resistance of the sample. Figure
PV28 shows the data obtained
for a phosphorus doping level
of about 1 ��1019 cm-3. The local
minimum visible in this data
(see insert) indicates the exis-
tence of an impurity band that
approximation fails in particular
for the heavily doped emitter and
back-surface-field regions of crys-
talline silicon solar cells, resulting
in an overestimation of its open-
circuit voltage. We calculated the
DOS of phosphorus-doped sili-
con, using photoluminescence
data of Bergensen et al. and
Schenk's quantum-mechanical
bandgap narrowing model. Figure
PV27 shows our results (symbols),
together with an empirical para-
meterisation (lines) of the DOS at
four different doping levels. This
technique allows us to determine
the DOS for doping densities
below 1 ��1019 cm-3. However, the
DOS of more heavily doped sili-
con cannot be extracted with suffi-
cient precision from photolumi-
nescence measurements.
In order to determine the DOS
of more heavily phosphorus-
doped silicon, we performed
low temperature (4.2 K) tunnel
spectroscopy measurements on
Schottky diodes. These meas-
urements determine the voltage
dependence of the differential
phosphorus-doped silicon from
these tunnel spectroscopy ex-
periments. This is expected
to lead to a further refinement
of the DOS parameterisation
shown in Figure PV27.
AAuuggeerr RReeccoommbbiinnaattiioonn
In a collaboration with Dr Jan
Schmidt and Mark Kerr from
the Australian National Uni-
versity (ANU) in Canberra, we
are investigating Auger recombi-
nation at intermediate injection
conditions, where the density of
injected carriers is similar to the
dopant density. This is the injec-
tion regime where most Si solar
cells operate. However, little is
known about Auger losses in
this regime because it is rather
difficult to measure or calculate
the Coulomb-enhanced Auger
recombination rate at such injec-
tion levels. The reasons are non-
linear charge carrier screening
effects and the influence of an
injection level dependent surface
recombination velocity. Screening
effects have been investigated in a
collaboration with Dr Andreas
Schenk from the ETH Zurich,
using the Thomas-Fermi screening
R E S E A R C H R E P O R T S
FIGURE PV27: AN EMPIRICAL PARAMETERISATION OF THE DOS
OF PHOSPHORUS-DOPED SILICON (SOLID LINE), OBTAINED FROM
PHOTOLUMINESCENCE MEASUREMENTS.
FIGURE PV28: DIFFERENTIAL RESISTANCE AS A FUNCTION OF
VOLTAGE, OBTAINED FROM TUNNEL SPECTROSCOPY MEASUREMENTS
ON A SCHOTTKY DIODE FABRICATED ON HEAVILY PHOSPHORUS-DOPED
SILICON. THE RESISTIVITY OF THE SILICON IS 0.0053 �CM, CORRESPON-
DING TO A DOPING LEVEL OF ABOUT 1 �� 1019 CM-3.
is still clearly separated from the
silicon conduction band, despite
the rather large doping level.
Using a new data evaluation
method, we are currently calcu-
lating the DOS of heavily
PV25 �
Additional transport mechanisms
are difficult to include in
“detailed balance” modelling
approaches that assume uniform
material and constant quasi-
Fermi levels, implying that carri-
ers can move “instantaneously”
and hence transport mechanisms
are not relevant. In order to
include transport, the device
must be divided into separate
sections, with transport across
the interfaces. Formulation of
this theoretical approach is con-
tinuing. Figure PV29 shows opti-
mised efficiency for a quantum
well solar cell, including hot car-
rier transport across the well and
Figure PV30 shows how the
solar cell efficiency for a single
device (only radiative recombina-
tion is considered) varies as the
fraction of carriers scattered into
the well increases. At f=1 (all car-
riers can be scattered into the
bottom of the well), the efficien-
cy equals that calculated for
tandems or the IPV effect, but
devices with hot carriers, the effi-
ciency can be higher.
dures and regulations for their
use are required. To ensure mar-
ket equity, energy market reform
must continue, removing biases
towards supply side and cen-
tralised options and ensuring
environmental and social issues
are considered in decision mak-
ing. Consistent industry, taxa-
tion and energy policies are
needed, with a long-term focus
on sustainability. Information is
needed for customers and plan-
ners on renewable resources,
technologies and systems.
To address price differentials,
R&D is needed on improved
production processes and lower
cost products, while market sub-
sidies are needed until target
penetration levels are reached.
Governments should purchase
renewables for their own use,
impose emission taxes on fossil
fuels and underwrite financing
packages to encourage confi-
dence and take-up.
Finally, the successful develop-
ment of a viable and robust
renewables industry in Australia
requires a comprehensive educa-
tion strategy, including familiari-
ty at community and school
level, technical skills for installa-
tion and maintenance and pro-
fessional training for designers,
engineers, architects and plan-
ners. The Key Centre is well
placed to address some of these
education requirements.
RReenneewwaabbllee EEnneerrggyy PPoolliiccyy GGrroouupp
In a joint UNSW/ACRE project,
Dr Watt is leading an ACRE
Renewable Energy Policy Group
(AEPG), with Professor Outhred
also a Group member. The AEPG
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS
� PV24
in the depletion region to the
behaviour of I-V curves are far
too approximate. With our more
general model, we were able to
reproduce the experimentally
observed maximum in the ideal-
ity factor of the I-V curves. It is
noted that this maximum ideali-
ty factor is well below the com-
monly assumed value of 2. We
also clarified why the ideality
factor decreases with increasing
cell voltage. Currently, we are
investigating losses where the
p-n junction reaches the surface,
and are extending our model to
grain boundaries crossing the p-
n junction.
QQuuaannttuumm WWeellll SSoollaarr CCeellllss
An investigation is being made
into the potential for novel solar
cell designs, such as the inclusion
of quantum wells, to increase the
theoretical efficiency limits of
homojunction solar cells. A key
issue surrounding quantum well
solar cells has been the conflict-
the density of such defects is
linear with proton flux, with an
introduction rate agreeing with
that reported by various re-
search groups.
These experiments provide a basis
for the quantification of losses in
parallel multijunction cells. We irra-
diated such cells as well, made of
high-purity crystalline material, in
the same manner as the PERL
devices mentioned above (see thin-
film reports). We are currently locat-
ing and quantifying loss mechanisms
related to the parallel multijunction
structure, in particular the impact of
p-n junction depletion region recom-
bination. This study will allow us to
better understand the performance
of such cells, and to quantify advan-
tages compared to commonly used
single-junction cells.
RReeccoommbbiinnaattiioonn iinn tthheeJJuunnccttiioonn DDeepplleettiioonn RReeggiioonn
Recombination in the p-n junc-
tion depletion region may be the
limiting loss mechanism in thin-
film cells, as this region extends
over a relatively large volume of
such devices. We simulated the
influence of depletion region
recombination on the I-V
curves by means of numerical
modelling. Using Dessis, we
solve the fully coupled semicon-
ductor equations without the
restricting assumptions often
found in literature (such as the
depletion region approximation,
assumptions on the quasi-Fermi
levels, etc.). We are also able to
numerically calculate recombi-
nation rates arising from more
than one defect level, as well as
from trap-assisted tunnelling.
We found that most analytical
models that relate Shockley-
Read-Hall recombination losses
ing modelling, particularly
detailed balance modelling, in
some cases supporting an effi-
ciency increase and in some case
showing that no efficiency
increase is possible. The key
implication of our modelling is
that it establishes criteria in the
search for devices that exceed
existing efficiency limits. It
demonstrates that in order for a
two-terminal solar cell to exceed
homojunction efficiency limits, it
must have features that allow
more than a single quasi-Fermi
level to exist within the device.
For example, two-terminal tan-
dem devices, which have experi-
mentally exceeded homojunction
efficiency limits, can do so since
the tunnel junction connecting
the various regions allow multi-
ple quasi-Fermi levels to exist.
Other methods by which multi-
ple quasi-Fermi levels can be
achieved are the impurity photo-
voltaic (IPV) effect and alterna-
tive transport mechanisms at
interfaces.
R E S E A R C H R E P O R T S
Renewable Energy Policy and Planning
University Staff:
Associate Professor Hugh Outhred
Project Staff:
Dr Muriel Watt
PPoolliiccyy RReeppoorrtt
A detailed study was prepared
for the Australian Cooperative
Research Centre for Renewable
Energy (ACRE) on “Policy
Options for Enhancing Elec-
tricity Industry Sustainability in
Australia”. In summary, the
report concludes that the critical
problems facing renewables in
Australia lie with market distor-
tions and lack of infrastructure,
both of which require a long-
term policy focus and consistent
industry support.
To ensure renewables can gain
market access, standard proce-
FIGURE PV29: OPTIMISED EFFICIENCY AS A FUNCTION OF THE OVERALL
BAND GAP, EG1, WITH F=0.5. EG2 IS THE WELL BANDGAP. FIGURE PV30: IMPACT OF TRANSPORT FACTOR, F, ON EFFICIENCY.
PV27 �
ment (to the pre-commercial
stage) of specialised equipment
for solar PV applications.
Notable users of the Centre's
DAD have been:
� ECO Design Foundation
General Technology
� Sussan
� Taronga Zoo
� National Parks and Wildlife
Service
� Harry Seidler and Associates
� Barry Webb and Associates
� energyAustralia
� Olympic Organising
Committee
� Federal Ministry of Health,
India
� Kenhill Engineers Pty Ltd
� Manly Council
� The Robinson Group
� Taylor Woodrow (Australia)
Pty Ltd
SSttaanndd AAlloonnee PPoowweerr SSuuppppllyy SSyysstteemmss
The Centre's expertise in
applied photovoltaics has been
effectively put to use by the
National Parks and Wildlife
Service (NPWS).
The success of the NPWS
Montague Island PV/diesel
hybrid system (with its subse-
quent reduction of fossil fuel
usage by 80%) has prompted
NPWS to install a 4 kW
PV/diesel hybrid system at
Green Cape on the far south
coast of NSW. This system was
commissioned in July 1999.
tender evaluation and thus
allowing NPWS to make an
informed decision.
Green Cape National Park has a
light house and two cottages. The
PV/diesel hybrid system supplies
power for up to 20 people.
As with Montague Island, in the
Green Cape project the PVSRC
was chosen for its non-partisan
expertise in renewable energy
systems. The DAD evaluated
the park's power requirements,
set tender specifications, con-
ducted a technical site visit for
tenderers, clarified the technical
content of the tenders during
PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS
� PV26
Design AssistanceDivision
Manager: Robert Largent
University Staff:
Dr Richard Corkish,
Dr Christiana Honsberg
Project Staff: Nick Shaw
The Centre's Design Assistance
Division (DAD) has a primary func-
tion to make available the Centre's
photovoltaic and systems expertise
to University and off-campus indi-
viduals and groups.
comprises leading Australian energy
policy experts and provides analysis
and advice to governments and
planners on critical policy issues
impacting on renewables.
NNSSWW LLiicceennccee CCoommpplliiaanncceeAAddvviissoorryy BBooaarrdd ((LLCCAABB))
Professor Outhred continued
his appointment with the LCAB,
with 1999 activities concerned
with retailer progress in meeting
environmental targets and with
distributors meeting least cost
planning obligations.
The DAD handles public en-
quiries regarding the technical
issues concerning Photovoltaics
(PV) and its associated equipment
by offering information, advice
and commercial contacts. Advice
ranges from RAPS information,
equipment suppliers, and system
sizing to recommending the best
locations in gardens to install
solar powered lights.
Technical support for industry is
diverse, ranging from enquiries
concerning commercially avail-
able solar technology to institut-
ing full projects for the develop-
FIGURE PV31: A 4 KWP PHOTOVOLTAIC ARRAY INSTALLATION AT GREEN CAPE NATIONAL PARK.
FIGURE PV32: MEMBERS OF THE GROOVE DIFFUSION AFTER
PACKING THE HOUSE AT THE CAT AND FIDDLE IN BALMAIN:
(LEFT TO RIGHT) NICOLA HARTLEY, OLIVER NAST, ALEXANDER SLADE,
KEITH MCINOTSH, JEFF COTTER, NICK SHAW, NADIA HARTLEY,
RUNGE CUTTA, AND JOHNNY WU.
(ONLY ENGINEERS WOULD NAME A BAND AFTER
THEIR RESEARCH PROCESSES.)
Groove Diffusion Apart from their teaching and research activities, PhDstudents, friends and faculty from the PhotovoltaicsSpecial Research Centre have formed a rock and rollband called the Groove Diffusion. The band membersmeet regularly on Wednesday nights and often performtheir original works at house parties and local pubs.Feedback from the masses indicates that music loversaround the world will soon know of the GrooveDiffusion.
R E S E A R C H R E P O R T S
� T29
Special Research Centre
for
Third Generation Photovoltaics
Start-Up Report
Special Research Centre
for
Third Generation Photovoltaics
Start-Up Report
T3 �
SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE FFOORR TTHHIIRRDD GGEENNEERRAATTIIOONN PPHHOOTTOOVVOOLLTTAAIICCSS � SSTTAARRTT-UUPP RREEPPOORRTT
Table of ContentsTable of ContentsDirector’s Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T6
Efficiency Losses in Standard Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T8
Tandem Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T9
Multiple Electron-Hole Pairs Per Photon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T10
Hot Carrier Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T11
Multiband Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T12
Thermophotovoltaics and Thermophotonics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T13
Financials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T14
Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T15
T5 �
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� T4
This success was undoubtedly aided
by the achievements of the Photo-
voltaics Special Research Centre,
whose maximum 9-year period of
ARC support terminated in
December, 1999. The new Centre
was one of a small number of such
Centres selected from applications
from around Australia across all
disciplines.
The Centre has activities clearly differ-
entiated from the Photovoltaics
Special Research Centre and the Key
Centre for Photovoltaic Engineering,
concentrating on a “third-generation”
of photovoltaic technology, not yet
fully conceived, let alone implement-
ed. I (Martin Green) will be the
Director of this new Centre with
Dr Armin Aberle, Deputy Director.
Dr Aberle will have special responsi-
bilities for the new Centre's experi-
mental programs.
Director’s ReportDirector’s Report
The new Centre will attempt to devel-
op ideas, able to be implemented in
thin-film form, likely to significantly,
rather than incrementally, improve
photovoltaic cell performance beyond
that of a single junction device.
Tandem stacks of solar cells of differ-
ing bandgaps are probably the best
known example of such a third-gen-
eration approach, whereby efficiency
can be increased merely by serially
stacking more cells. The new Centre
will explore approaches capable of
similar efficiency but using more
innovative “parallelled” approaches.
The following “start-up” report con-
tains more information on some of
the ideas to be explored and progress
made since the original application for
the new Centre was prepared. The
motivation for this initiative comes
from the premise that the manufac-
turing costs of mature products pro-
duced in increasingly large volume
eventually approach the costs of the
constituent materials.
This is already the case for “first-gen-
eration” wafer-based photovoltaics
where material costs (wafers, glass,
and encapsulants) account for over
70% of manufacturing cost. It will
eventually be the case for “second-
generation” thin-film technology
where the costs of glass or other
encapsulants will dominate. This
leaves efficiency as the key parameter
in determining the long term costs
and viability of photovoltaics.
Fortunately, there seems to be enor-
mous scope for improving photo-
voltaic energy conversion efficiency.
Most present day product is bounded
by a fundamental efficiency limit of
33%, struggling to attain half this
value in practice. However, the ther-
modynamic limit on the conversion of
sunlight to electricity is 93%. This
gives enormous scope for improve-
ment, provided
sufficiently innovative ideas can be
generated to take full advantage in the
progress in materials technology
expected over the next 20 years.
In the words of one reviewer of the applica-
tion for the new Centre: “The proposal
reminds me of the situations that existed
prior to other great semiconductor technology
inventions like the transistor and the integrat-
ed circuit. Both inventions came from perceived
requirements of the next generation of elec-
tronic devices in the marketplace. There were
no road maps when the groups began - just a
clear definition of the required result”.
I think this comment well
captures the excitement and potential
associated with the work of the new
Centre. I look forward to the challenge
of this potential to reality.
D I R E C T O R ’ S R E P O R T
PPrrooffeessssoorr MMaarrttiinn GGrreeeenn,,DDiirreeccttoorr,,SSppeecciiaall RReesseeaarrcchh CCeennttrree ffoorr TThhiirrdd GGeenneerraattiioonn PPhhoottoovvoollttaaiiccss
The University has been successful in its application for
an Australian Research Council (ARC) Special Research
Centre in Third Generation Photovoltaics, which
commenced in January, 2000.
SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE FFOORR TTHHIIRRDD GGEENNEERRAATTIIOONN PPHHOOTTOOVVOOLLTTAAIICCSS � SSTTAARRTT-UUPP RREEPPOORRTT I N T R O D U C T I O N
T7 �� T6
in series. In this case, the cell stack
operates essentially as a two termi-
nal device, as for a standard cell.
Such “monolithic” tandem
cells, involving up
to three different
bandgap cells
a r e
now in
p r o d u c t i o n
for spacecraft, with
energy conversion effi-
ciency up to 30%. They are
also used to improve stability in amor-
phous silicon solar cells, where the best
commercial triple junction modules
have more modest efficiencies in the
6-7% range.
High efficiency is possible, in princi-
ple, merely by increasing the number
of cells in the stack. In practice, not
only does this increase complexity, it
increases sensitivity to spectral varia-
tions in sunlight, unless separate con-
nections to each cell are made.
Although the tandem cell approach is
important in demonstrating the
feasibility of “third-generation”
approaches giving efficiencies close to
thermodynamic limits, it will not be
the focus of efforts of the new
Centre. The new Centre will seek
to investigate and develop approaches
of a more “parallel” nature than
the “serial” nature of the tandem
approach.
“Hot carrier” cells provide an example
of such an integrated, “parallel”
approach. One of the main loss
mechanisms in a conventional solar
cell is the thermalization of photo-
excited carriers with the atoms in the
crystal lattice. The tandem approach
reduces the magnitude of this loss. A
options discussed in the following sec-
tions and for related “proof-of-con-
cept” experimental work. The objec-
tive is, within nine years, to have
developed one or more of the most
promising options to the stage where
it can be commercially evaluated.
Figure T3 diagramatically shows the
advantages that may be expected by
the successful implementation of a
thin-film third-generation approach
compared to both first- and
second-generation approaches. First-
“hot carrier”
cell seeks to
avoid this
loss by re-
stricting energy
loss by phonon emis-
sion in the cell. Very little
prior theoretical or experimen-
tal work has been done in this area.
The increased flexibility offered by the
emerging field of low-dimensional
semiconductors would seem to have
considerable potential here. Of partic-
ular interest are prospects for
IntroductionIntroduction
approach limits the potential for
cost reduction and hence the possi-
ble long-term impact of the tech-
nology. It seems likely that a mature
thin film approach will displace first-
generation technology over the next
10 years.
Since the energy conversion efficien-
cy of any such second-
generation technolo-
gy is unlikely to
reach even
that of
t h e
first-genera-
tion (15%), this leaves
improved thin-film energy conver-
sion efficiency as the area of
highest impact for future
research. There would seem to be
enormous scope for improve-
ment given that the thermody-
namic limit upon the efficiency of
conversion of sunlight to electric-
ity is 93%, although the route to
such high efficiency is at present
unclear. The development of
concepts and supporting technol-
ogy for a high efficiency “third-
generation” photovoltaic technol-
ogy based on thin films is the pri-
mary aim for the new Centre for
Third Generation Photovoltaics.
Director:
Professor Martin Green
Deputy Director:
Dr Armin Aberle
Co-Applicants:
Dr Pietro Altermatt
Mr Andrew Brown
Dr Patrick Campbell
Dr Richard Corkish
Dr Mark Gross
Dr Mark Keevers
Dr Aihua Wang
With the acceptance of the grow-
ing importance of sustainable
energy generation technologies,
photovoltaics is clearly an
important industry for a
research focus within
Australia. Not only
does such
research have to
address the short to medium
term concerns of the local indus-
try but, for the industry to retain
its leadership role, the research
also has to remain at the forefront
in investigating future options, so
that the most relevant of these are
identified early and the appropriate
investments made.
In the past, the research work
likely to make the largest impact
upon the industry has been that
allowing a transition from first-
generation silicon wafer-based
technology (Figure T1), to that of
thin films supported on a foreign
substrate, such as the polycrys-
talline silicon film on glass exam-
ple of Figure T2 (“second-gener-
ation” technology). The material
intensiveness of the wafer-based
The limiting efficiency of 93% is
slightly lower than the Carnot effi-
ciency of 95% (based on a tempera-
ture of 6000 K for the sun's photo-
sphere, and a 300 K terrestrial tem-
perature). This is because the latter
is based on the net energy transfer
between the sun and the cell. The
lower figure is more pragmatic in
regarding the energy radiated by the
cell back to the sun as a loss.
In the past, several photovoltaic
approaches have been shown, in
principle, to be capable of perform-
ance quite close to this limit.
One, based on multi-
ple or tandem cells, is
quite well developed and
understood. By splitting
the solar spectrum into nar-
row wavelength bands and convert-
ing these in separate cells of appro-
priate energy bandgap, energy con-
version efficiency can be increased.
In the limit of an infinite number of
cells, the limiting conversion efficien-
cy for direct sunlight is 86.8%. An
elegant development of this
approach is to have the cells stacked
in order of decreasing bandgap. The
uppermost wide bandgap cell will
absorb the high energy photons it is
able to convert, passing photons of
energy below its bandgap through to
the underlying cell, where the process
continues. A further simplification
occurs, in practice, if each cell con-
verts the same number of photons,
so that their output currents are
matched and they can be connected
FIGURE T2: AN EXAMPLE OF “SECOND-GENERATION”
THIN-FILM TECHNOLOGY (MODULE FABRICATED ON
PACIFIC SOLAR'S SYDNEY PILOT LINE DURING 1998,
BASED ON THIN-FILMS OF POLYCRYSTALLINE SILICON
ON GLASS, AGAIN UNSW-DEVELOPED TECHNOLOGY).
FIGURE T1: “FIRST-GENERATION”
WAFER-BASED TECHNOLOGY (BP
SOLAREX SATURN MODULE, THE
PHOTOVOLTAIC PRODUCT MANU-
FACTURED IN THE HIGHEST VOL-
UME BY THE COMPANY IN EUROPE
DURING 1999, USING UNSW
BURIED CONTACT TECHNOLOGY).
Australia is already a key player in photovoltaics (solar elec-
tricity) as the largest manufacturer per capita, a research
leader, and the developer of the current industry-leading
“buried contact” cell technology.
FIGURE T3: EFFICIENCY AND COST PROJECTIONS FOR FIRST-, SECOND- AND
THIRD-GENERATION PHOTOVOLTAIC TECHNOLOGY (WAFERS, THIN-FILMS,
AND ADVANCED THIN-FILMS, RESPECTIVELY).
“phononic” engineering to allow “hot
carrier” populations to be maintained
and the design of contacts to allow the
required “isoentropic cooling” of
these populations. Energy conversion
efficiency essentially equal to the infi-
nite tandem cell case is obtainable, in
principle, if these issues can be satis-
factorily addressed.
The new Centre aims to become an
international focal point for efforts to
explore a range of such “parallelled”
generation technology, due to its
material intensiveness, is unlikely to
attain manufacturing costs below
US$150/m2 or US$1/Watt. Second-
generation thin film technology may
ultimately reach costs of US$30/m2
or below US$0.50/Watt. Although
third-generation may not reach the
same low costs per unit area as
second-generation technology, the
resulting high efficiency could
result in very low costs below
US$0.20/Watt.
Tandem Cells
T9 �
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� T8
Efficiency Losses in Standard CellsEfficiency Losses in Standard Cells
tion can be used to derive quite funda-
mental limits on achievable solar cell
performance. This approach revisits
“black body” radiation, the topic that
stimulated the birth of quantum
mechanics during investigations by
Max Planck in 1900.
Basically, radiation from the sun
approximates that from a “black body”
held at a warm 6,000 K, the tempera-
ture of the sun's photosphere (a black
body is just a perfect absorber and
hence emitter of light). The energy dis-
tribution of this radiation is described
by a formula developed by Planck. In
Shockley and Queisser's approach, the
solar cell is also modelled by a black
body, but at the more typical terrestrial
temperature of 300 K. They realized
that Planck's formula would need to be
modified for a device where the light
was generated by recombination
between electrons and holes at differ-
ent potentials in the conduction and
valence band. In fact, the emitted radi-
ation increases more than exponential-
ly as the voltage across the cell increas-
es for photon energies above the
bandgap. This is well known qualita-
tively from light emitting diodes and
the semiconductor laser areas.
When open-circuited, the voltage of
the ideal cell builds up so that the num-
ber of above bandgap photons emit-
ted as part of this voltage - enhanced
radiation balances those in the incom-
ing sunlight. At voltages below open-
circuit, the number of emitted photons
is less, the difference between incom-
ing and outgoing being due to elec-
trons flowing through cell terminals.
In this way, Shockley and Queisser
were able to show that the perform-
A key fundamental loss process is
process 1, whereby the photoexcited
electron-hole pair quickly loses any
energy it may have in excess of the
bandgap. A low energy red photon is
just as effective in terms of outcomes
as a much higher energy blue photon.
This loss process alone limits conver-
sion efficiency of a cell to about 44%.
Another important loss process is
process 2, recombination of the pho-
toexcited electron-hole pairs. This can
be kept to a minimum by using semi-
conductor material with appropriate
properties - especially high lifetimes
for the photogenerated carriers.
This can be ensured by eliminating all
unnecessary defects. The lifetime
is then determined by radiative
recombination processes in the cell,
the inverse process to the photoexcita-
tion process.
As shown in 1960 by William Shockley
and Hans Queisser, this symmetry
between light absorption and light
emission during radiative recombina-
ance of a standard cell was limited to
31.0% efficiency for an optimal cell
with a bandgap of 1.3 eV (electron
volts). This is lower than the
figure of 44% previously mentioned
since the output voltage of the cell is
less than the bandgap potential, with
the difference made up by the voltage
drops at the contact and junction.
These drops can be reduced if the
sunlight is focussed to increase the
photon density striking the cell. Under
the maximum possible sunlight con-
centration (46,200 times!), the limiting
efficiency increases to 40.8%. How-
ever, only the direct component of
sunlight can be focussed in this way.
This is not an issue when above the
earth's atmosphere. However, sunlight
is scattered by this atmosphere so that
only about 75% of the light reaching
the earth's surface is direct. Only this
component can be converted with this
efficiency, even in principle.
However, as the figure under maximal
concentration gives the highest numer-
ical value, this direct light conversion
efficiency is a useful figure and is use-
ful in comparing the ultimate efficien-
cy potential of any given approach.
This efficiency is also more directly
comparable with the results from clas-
sical thermodynamics.
For example, the conversion
efficiency of energy from a source at
6,000 K with a sink temperature of
300 K is limited by the Carnot effi-
ciency (1 - Tsink/Tsource) to 95.0%.
However, this value does not count the
photons emitted by the cell as a waste,
since it assumes they get back to the
sun, helping it to maintain its tempera-
ture! A limit that regards these pho-
tons as a loss while assuming the
process is reversible, as in the
Carnot limit, is 93.1%. Some of the
schemes to be investigated in the new
Centre can approach this limit
reasonably closely.
FIGURE T4: LOSS PROCESSES
IN A STANDARD SOLAR CELL:
(1) THERMALISATION LOSS;
(2) AND (3) JUNCTION AND
CONTACT VOLTAGE LOSS; (4)
RECOMBINATION LOSS.
Loss processes in a standard single junction cell are indi-
cated in Figure T4, which shows the energy of electrons
in the cell as a function of position across it. Photons in
sunlight excite electrons from the valence band across
the forbidden gap to the conduction band.
Tandem Cells
tively. Having to independently oper-
ate each cell is a complication best
avoided. Usually cells are designed so
that their current outputs match so
that they can be connected in series.
Fortunately, just stacking the
cells with the highest bandgap
cell uppermost as shown in
Figure T5 automatically achieves
the desired filtering. Perfor-
mance increases as the number
of cells in the stack increases,
with a direct sunlight conversion
efficiency of 86.8% calculated
for an infinite stack of independ-
ently operated cells. For such a
large number of cells, each
would operate as a Geiger count-
er, each patiently waiting for a
photon of the correct energy to
get through the filter.
Fortunately, the performance is
quite good even with a relatively
small number of cells in the
stack, increasing from the single
cell value of 40.8% to 55.9%,
63.8% and 68.8% as the number
of independently operated cells
increases to 2, 3 and 4, respec-
Tandem cells are already in com-
mercial production for two distinct-
ly different technologies. Double
and triple junction cells based on
the GaInP/GaAs/Ge system have
been developed for use on space-
craft with terrestrial sunlight con-
version efficiencies approaching
30%. Quadruple junction devices
with efficiencies approaching 40%
are presently under development
for such use. Tandem cells are also
used to improve the performance
and reliability of terrestrial amor-
FIGURE T5: AN ALL-SILICON
TANDEM CELL CONCEPT BASED
ON SI/SIO2 SUPERLATTICES.
The key loss process 4 of Figure T4 can be largely eliminat-
ed if the energy of the absorbed photon is just a little higher
than the bandgap of the cell material. This leads to the con-
cept of the tandem cell, where multiple cells are used with
different bandgaps, each converting a narrow range of
photon energies close to its bandgap.
FIGURE T6: AN ALL-SILICON TANDEM CELL CONCEPT
BASED ON SI/SIO2 SUPERLATTICES
This additional constraint slightly
reduces achievable performance.
More importantly it makes the design
very sensitive to the spectral content
of the incident sunlight. Once the
output current of one cell in a series
connection drops more than about
5% below that of the next worst cell,
the best that can be done for overall
performance is to short-circuit the
low output cell, otherwise it will con-
sume, rather than generate power. A
by-pass diode that limits this
consumed power is the most practical
way of implementing this short-
circuit to date. Some of the other
high efficiency approaches discussed
below do not suffer from this spectral
sensitivity.
phous silicon cells with stabilised
efficiencies up to 12% confirmed
for triple junction cells based on the
Si:Ge:H alloy system. Modules with
efficiencies in the 6-7% range are
available incorporating double and
triple junction devices.
Since this technology is well
understood and developed,
Centre programs will focus on
alternatives discussed below.
However, one area of interest
will be the use of Si/SiO2 super-
lattices potentially to allow sili-
con's bandgap to be controlled.
Such control would make an all-
silicon tandem cell as shown in
Figure T6 feasible.
E F F I C I E N C Y L O S S E S
T A N D E M C E L L S
Multiple Electron-Hole Pairs Per Photon
T11 �
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Multiple Electron-Hole Pairs Per Photon
Raman scattering of high energy
photons. Raman scattering is a gener-
ic term applied to the inelastic scat-
tering of photons (scattering
processes that result in a change in
photon energy also, usually, in direc-
tion). In the semiconductor field,
Raman scattering by light interaction
with lattice vibrations (phonons) is
well known, and forms the basis of a
well known characterisation
approach. Formally, the scattering
process involves the creation of a
“virtual” electron-hole pair by the
photon in a process that conserves
momentum but not necessarily ener-
gy. The virtual pair remains viable for
Evidence for the creation of more
than one electron-hole pair by high
energy photons has been document-
ed since the 1960's for Si and Ge,
usually attributed to impact ioniza-
tion by the photoexcited carriers.
More recently, the limiting efficiency
possible for an idealized cell capable
of taking full advantage of this
impact ionization effect has been rig-
orously analysed. A limiting efficien-
cy of 85.4% has been calculated for a
cell of bandgap approaching zero,
allowing, on energy grounds at least,
many electron-hole pairs to be gener-
ated by each incident photon.
In reality, the measured effect in any
material to date is so weak so as to be
able to produce negligible improve-
ment in device performance. In
experimental devices, competitive
processes for the relaxation of the
high energy photoexcited carriers are
too efficient.
One aspect that the Centre will be in
a good position to explore is the via-
bility of improving the relative effec-
tiveness of the impact ionization
process. For example, alloying Ge
with Si in the surface region of a cell,
where high energy photons are
absorbed, will change the relative
dynamics, possibly for the better.
Similarly, incorporation of a Si/SiO2
superlattice in this region, of interest
on other grounds, will similarly have
an impact on these dynamics.
Preliminary work is already underway
in the former area.
The Centre also plans to conduct
more innovative work based on the
the virtual pair interacts. (A very sim-
ilar process explains the high
refractive index characteristic of
semiconductors. The virtual pair,
in the more general case, relaxes
elastically, by emitting a photon of
the same energy as the original
one, in the original direction. This
process slows the propagation of
light compared to that in vacuum
by a factor equal to the magnitude
of the refractive index).
Rather than the standard Raman
process, the Centre will investigate
the feasibility of enhancing a related
Raman scattering process that
involves the virtual pair relaxing to
other states in their respective bands
during the second stage of the
process involving, in this case, pho-
ton emission. The net result would
then be that a photon was absorbed
in creating an electron-hole pair, with
a second photon emitted of energy
up to that of the surplus energy of
the first photon above the bandgap.
One way of enhancing such effects
would be to use semiconductor
material with only a finite band of
allowed states in both conduction
and valence bands (Figure T7). This
would remove competitive processes
for the absorption of high energy
photons, promoting virtual absorp-
tion processes.
An analysis of the efficiency of
cells based on such Raman scatter-
ing shows that they are con-
strained by identical bounds to
those on cells based on impact
ionisation. In principle, 85.4%
efficiency is possible from such
cells. The difference between the
approaches may prove to be dif-
ferences in the practicality of
implementation.
If, instead of giving up their energy as heat loss, the high
energy electron-hole pair instead use their excess ener-
gy to create additional electron-hole pairs, higher
efficiency would be possible in principle.
FIGURE T7: PHOTOVOLTAIC
DEVICE BASED ON RAMAN
LUMINESCENCE
a finite time determined by the ener-
gy imbalance. During this period, for
Raman phonon scattering, the virtual
pair relaxes emitting a photon of an
energy that differs from that of the
original photon by the energy of the
lattice vibration (phonon) with which
The various time constants involvedcan be appreciated by imagining adirect bandgap cell illuminated by ashort pulse of monochromatic laserlight. Such a pulse creates electrons inthe conduction band and holes in thevalence band of very distinct energyand momentum as in Figure T9.Collisions of these photoexcited carri-ers occur in less than a picosecond,tending to smear out this distribution.Similar collisions were studied byLudwig Boltzmann, in his study ofcollisions between gas molecules, inthe 1800s. He showed that moleculesevolve towards a distribution in energywith an exponentially decaying tailwith a characteristic decay constantequal to the “thermal energy”, kT.
Electrons behave similarly, apart fromslight departures near the band edgesince they are fermions. After a num-ber of collisions, the initially peakeddistributions becomes broader andtends towards the type of distributionderived by Boltzmann. If carriers col-lide elastically only with carriers of thesame type, no energy is lost from thisgroup of carriers. The temperature ofthe “hot carrier” distribution is deter-mined by the total number of carrierscreated by the laser pulse and the totalenergy given to each carrier type.Different temperatures are possiblefor electrons and holes unless efficientat sharing energy.
In the next phase, collisions with thelattice atoms become important.These result in energy loss to lattice(phonon emission). During this phase,the number of electrons and the num-ber of holes remain constant (neglect-ing impact ionization), but the average
before they get too far into the recom-bination stage of this decay sequence.A hot carrier cell has to catch thembefore the carrier cooling stage.Carriers either have to traverse the cellquickly or cooling rates have to beslowed. Special contact designs to pre-vent contacts from cooling the carriersmay also be required.
Apart from two theoretical studiesand experiments showing reducedcooling rates in semiconductorsuperlattices, little prior work hasbeen undertaken on hot carriercells. The Centre seeks to developspecific cell designs paying partic-ular attention to contact design.Work to date at the Centre showsthat the limiting efficiency of thisapproach is intermediate betweenthe 85.4% and 86.8% values ofthe two previous sections.
FIGURE T9: ENERGY RELAXATION OF CARRIERS AFTER A
SHORT, HIGH-INTENSITY LASER PULSE AT t = 0.
When photoexcited carriers collide elastically with one another,
no energy is lost. It is inelastic collisions with the atoms of the cell
material that result in an energy loss (through phonon emission).
In principle, if such atomic collisions can be avoided during the time
it takes a photogenerated carrier to traverse the cell, the energy
loss associated with process 1, of Figure T4 can be avoided.
FIGURE T8: HOT CARRIER CELL CONCEPT.
CARIERS STAY HOT, WHILE THE CELL STAYS COOL.
energy and carrier temperaturedecrease. The temperature of elec-trons and holes equalise and bothreduce towards the temperature of thehost material.
Finally, recombination in the semicon-ductor becomes important. The distri-butions of electrons and holes retainthe same general shape, determined bythe ambient temperature, but thenumber of carriers at each energyreduces until finally reaching the levelsprior to the laser pulse. A standard cellis designed to collect the carriers
Hot Carrier CellsHot Carrier Cells
M U L T I P L E E L E C T R O N - H O L E
H O T C A R R I E R C E L L S
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Multiband CellsMultiband Cells
more tolerant to spectral varia-
tions in sunlight than the series
tandem case.
Centre work has also already
resolved an issue that has been
controversial within the photo-
In recent Centre work, this the-
ory has been extended to an n-
band cell and some possible
implementation approaches dis-
cussed. These include excita-
tions between minibands in
semiconductor superlattices, if
phonon relaxation processes can
be controlled, the use of semi-
conductors with multiple nar-
row valence and conduction
bands, such as I-VII and I3-VI
compounds or the use of high
concentrations of impurities
such as rare-earth elements to
form multiple impurity bands in
wide bandgap semiconductors.
The limiting efficiency for an n-
band cell has been shown to be
identical to the 86.8% figure for
a large stack of tandem cells.
However, the effective cell con-
nections in the n-band approach
show much more redundancy
than in a series connected
tandem cell (Figure 10). This
suggests the approach may be
voltaic community. This is
whether an idealised cell incor-
porating multiple quantum wells
can exceed the efficiency of an
idealised standard cell. By sug-
gesting the structure of Figure
T12, which shows a multiple
quantum well cell that meets all
the requirements, in principle,
need to attain the limiting 3-
band cell performance, the
question is now answerable in
the affirmative.
FIGURE T10:
THREE BAND SOLAR CELL.
FIGURE T11: FOUR BAND CELL AND EQUIVALENT CIRCUIT.
FIGURE T12: MULTIPLE QUANTUM WELL SOLAR CELL
MEETING THE CONSTRAINTS OF 3-BAND THEORY.
Standard cells rely on excitations between the valence and
conduction band of a semiconductor. A recent analysis has
shown efficiency advantages if a third band, nominally an
impurity band, is included in the analysis (Figure T10).
Thermophotovoltaics & ThermophotonicsThermophotovoltaics & Thermophotonics
Basically, the heated device acts
as an emitter of narrow band-
width light within an energy, kT,
of its bandgap energy. This near-
monochromatic light can be con-
verted very efficiently by the cell.
Moreover, light emitted by the
cell is recycled back to help drive
the light emitting diode.
Additionally, since the voltage
This source may be an element
heated to high temperature, such
as by using a gas burner. High
efficiency is possible in this case
for two reasons. One is that the
light source may emit a narrower
bandwidth of light than the sun,
such as the case when heated
ceramics containing rare-earth
elements are used as the source.
A second reason is that energy
from the cell, such as that
reflected or emitted as light, can
be recycled to the source increas-
ing overall efficiency.
In the original Centre applica-
tion, a development of this
approach dubbed “thermopho-
tonics” was described and has
since been the subject of a
Centre patent application. In this
case, the exponentially enhanced
light output of a device where
the light is generated by recom-
bination between carriers in a
conduction and valence band, as
described earlier, is used to
advantage.
Figure T13 shows the basic
arrangement which is nearly sym-
metrical. Two idealised diodes act-
ing as solar cells/light emitters
face each other and are connected
by a load. Heat is supplied to one
to heat it hotter than the other and
heat is extracted from the other to
maintain it at a cooler temperature.
The devices are optically coupled
but thermally isolated. The combi-
nation is able to convert heat sup-
plied to the hotter device to elec-
tricity in the load with an efficien-
cy approaching the Carnot effi-
ciency, in principle.
results in power dissipation in the
load. If a non-absorbing, narrow
band fitter is placed between the
cell and diode, the efficiency of
conversion of heat supplied to the
diode to electrical power in the load
can approach the Carnot efficiency.
The efficiency is lower without this
filter due to the thermal smearing
represented by the effective kT
energy bandwidth.
With on-going evolution in device
design, both experimental solar
FIGURE T13: THERMOPHOTONIC CONVERSION.
Thermophotovoltaics is a well-established branch of
photovoltaics where a light from a heated body other
than the sun is used as the illuminating source
across this diode, which determines
the energy of the incoming elec-
trons, is less than its bandgap
potential, which determines the
energy in the emitted photons, the
diode has to be heated to maintain
its temperature if operating at high
quantum efficiency due to the con-
sequent refrigerating action associ-
ated with this energy gain.
Since the same current flows in the
cell and source diode, the voltage
across the diode will be smaller than
that across the cell when the diode
is at higher temperature. This
cells and light emitting diodes are
approaching the stage where inter-
nal recombination is limited by
radiative processes, a prerequisite
for the success of this scheme. If
used to convert solar radiation in
conjunction with a thermal
absorber, energy conversion
efficiency up to 85.4% is obtainable
in principle. Alternatively, the
approach could be used for maxi-
mally efficient conversion of fossil
fuels or waste heat. It may prove
ideal for the latter when the heat is
available at low temperature.
M U L T I P L E B A N D C E L L S
T H E R M O P H O T O V O L T A I C S
Centre Director, Professor Martin
Green, presented an invited keynote
paper outlining some of the ideas the
Centre would be working on at the
The Third International Conference
on Low Dimensional Structures and
Devices in September, 1999 at
Antalya, Turkey. He is also scheduled
to give a paper on the same topic at
the 16th European Photovoltaic Solar
Energy Conference, Glasgow in May
and an invited paper at the 8th
International Symposium on Nano-
structures: Physics and Technology in
St. Petersburg in June. Provisional
patent specifications have been filed,
or prepared for filing, on some of the
ideas believed innovative relating to
multiband cells, thermophotonic con-
version, and Raman luminescence. A
number of journal papers have either
been submitted for publication or are
awaiting review, pending patent filing,
as indicated below.
Journal PublicationsM.A. Green, “Potential for Low
Dimensional Structures in Photo-
voltaics”, Materials Science and
Engineering B, (in press).
ConferencePublicationsM.A. Green, “Potential for Low
Dimensional Structures in Photo-
voltaics”, Conference, The Third
International Conference on Low
Dimensional Structures and Devices,
Antalya, Turkey, September, 1999.
M.A. Green, “Third Generation
Photovoltaics: Advanced Structures
Capable of High Efficiency at Low
Cost”, 16th European Photovoltaic
Solar Energy Conference, Glasgow,
May, 2000, to be published.
M.A. Green, “Prospects for
Photovoltaic Efficiency Enhance-
ment Using Low Dimensional
Structures”, 8th International Sym-
posium on Nanostructures: Physics
and Technology, St. Petersburg, June,
2000, to be published.
Green, M.A., “Multiple Band
Luminescent Photovoltaic Con-
verters: General Theory and
Comparison to the Tandem Solar
Cell Approach”, (in press).
Green, M.A., “Third Generation
Photovoltaics: Ultra-High Efficiency
at Low Cost”, (in press).
Green, M.A. and Wenham, S.R.,
“Thermophotonic Conversion: A
New Conversion Concept for Low
Grade Heat”, (in press).
Green, M.A., “Potentially High
Efficiency Solar Cells Based on
Raman Luminescence”, (in press).
Green, M.A., “Limiting Mono-
chromatic Photovoltaic Conversion
Efficiency”, awaiting review.
Green, M.A., “Fermi-Dirac, Bose-
Einstein and Related Integrals and
their Inverses for Negative Argu-
ments”, prepared for publication.
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� T14
FinancialsFinancialsResearch and Development Fund.
The Centre has also been advised
that its application for an interna-
tional grant under the Japanese
Research Institute of Innovative
Technology for the Earth (RITE)
Research Proposal Competition
has been successful.
The above funds will be used to
maintain and develop laboratory
The initial Australian Research
Council grant is $1,540,000 over
the 2000-2002 triennium. These
funds are being augmented by an
Australian Research Fellowship
and considerable support from the
University of New South Wales.
Additional funding of up to
$218,540 over the same period has
been awarded under the New
South Wales Sustainable Energy
facilities for this work, for the sup-
port of postgraduate students,
postdoctoral researchers and visit-
ing academics wishing to become
involved in this research, and for
the support of collaborative
research with local and overseas
institutions, such as by hosting
workshops and participating in
staff exchange.
PublicationsPublications
1999
Key Centre
for
Photovoltaic
Engineering
UUNNSSWW
1999
Key Centre
for
Photovoltaic
Engineering
UUNNSSWW
The University of New South Wales
Key Centre for Photovoltaic Engineering
Electrical Engineering Building
The University of New South Wales
UNSW SYDNEY NSW 2052
AUSTRALIA
Tel+61 2 9385 4018 Fax+61 2 9662 4240
E-mail: [email protected] http://www.pv.unsw.edu.au
Annual Report
1 KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG D I R E C T O R ’ S R E P O R T
K3 �� K2
The University of New South
Wales's (UNSW) commitment to
provide the Key Centre with access
to income earned, such as through
EFTSUs and research quantum, has
been achieved through the establish-
ment of the Centre for Photovoltaic
Engineering. This Centre conforms
to the standard school structure
adopted throughout UNSW and
therefore becomes an "umbrella"
Centre encompassing all the photo-
voltaic and related activities such as
its Key Centre and two Special
Research Centres. However,
UNSW’s commitment to establish
the Centre for Photovoltaic
Engineering as an independent
budget unit or autonomous centre,
is dependent upon the demonstra-
tion of sustainability. A decision on
this issue will not be made prior to
the three yearly review of the Key
Centre. Nevertheless, with the sup-
port of the Dean of Engineering,
the Centre for Photovoltaic Engin-
eering from a financial perspective,
is being treated as if it were an inde-
pendent budget unit with an income
allocation directly from the Faculty.
The first year of operation has
therefore been a challenging transi-
tion year due to the complicated
process of establishing this financial
independence.
In the educational area, the pri-
mary new initiative of the Key
Centre has been the development
and establishment of the new
Bachelor of Engineering in
Photovoltaics and Solar Energy.
Following extensive curricula
development, approval for the new
program was granted at School,
Faculty, Academic Board and
University Council levels. UAC list-
ing for the new Bachelor of
Engineering was achieved in 1999,
with first enrolments taking place
in the year 2000. The performance
measure target of enrolling 25-35
students in the year 2000 was com-
fortably achieved with 41 new stu-
dents officially enrolling in the first
year of the program. Importantly
the new program, even though in
its infancy, has demonstrated its
ability to attract the highest quality
students as discussed later in the
reports. Another aim of the Key
Centre has been to attract new
PhD enrolments, primarily
through attracting new top quality
staff capable of carrying out the
corresponding supervision. To this
extent, the Key Centre has been
extremely fortunate to attract two
new academic staff members, Dr
Armin Aberle and Dr Jeff Cotter
who in combination have taken on
in Australia. The successful collabo-
ration with Eurosolare has led to a
new license agreement and corre-
sponding technology transfer in
recent months. In the educational
area, one of the more important col-
laborations has been with the
Australian CRC for Renewable
Energy (ACRE). This new collabora-
tion commenced in April 2000 and
involves provision of funding from
ACRE to the Key Centre to support
educational activities in the areas of
distance learning via the Internet,
school programs and community
education. A memorandum of
understanding is also currently being
negotiated to establish educational
collaboration with the other three
institutions with strong interests in
photovoltaics and renewable energy,
namely Murdoch University, Curtin
University and the Australian
National University.
Many of the Key Centre’s achieve-
ments and activities have been pub-
lished through international confer-
ences, journals, media interviews,
newspaper and magazine articles,
and trade journal publications.
Considerable emphasis has been
placed on the promotion of the Key
Centre and its activities, particularly
with regard to disseminating infor-
mation about the new Bachelor of
Engineering in Photovoltaics and
Solar Energy. Another avenue for
information dissemination has been
through the fortnightly seminar pro-
gram run jointly between the Key
Centre for Photovoltaic Engineering
and the School of Electrical
Engineering under the direction of
Associate Professor Hugh Outhred.
In summary, the Key Centre for
Photovoltaic Engineering has
achieved all the outcomes expected
for the first year of operation, in
both teaching and research.
The activity plan and projected
expenditure for the next twelve
months remain as indicated in the
original Key Centre proposal. In par-
ticular, the development of the new
Master of Engineering Science in
7 post-graduate research students
since the commencement of the
Key Centre.
A necessary outcome for the Key
Centre has been the implementation
of its proposed management struc-
ture, the effectiveness of which is
best assessed through evaluation of
the effectiveness of the Key Centre
activities. The management commit-
tee meets fortnightly with the only
significant change to the manage-
ment structure originally proposed
being the direct reporting of the col-
laborative research program man-
agers to the Centre director.
In the areas of links and national
focus, the Key Centre has been quite
effective at establishing new collabo-
rations with industry related organi-
sations, manufacturers and other
institutions. In the area of industry
funded collaborative research, the
Key Centre has successfully negotiat-
ed a collaborative program with each
of the Australian photovoltaic manu-
facturers, BP Solar, Pacific Solar and
Solarex. The most recent of these to
be negotiated has been with Solarex,
with the project due for commence-
ment in 2001. Another company,
Eurosolare from Italy, has expressed
an interest in possible manufacturing
Director’s ReportDirector’s Report
PROFESSOR STUART R. WENHAM,
DIRECTOR, KEY CENTRE FOR PHOTOVOLTAIC ENGINEERING
THE SOLAR ENERGY REACHING THE EARTH’S SURFACE IN
ONE DAY EXCEEDS MANKIND’S TOTAL ENERGY REQUIREMENTS
FOR THIRTY YEARS.
The first year of operation has been a challenging but exciting
period for the Key Centre with the industry booming and
excellent progress made against many of the performance
measures and expected outcomes. Perhaps of greatest impor-
tance has been the granting of financial independence from the
School of Electrical Engineering.
This honours the University's commitment towards the
longer-term establishment of an autonomous centre. This has
been an essential precursor to the Key Centre demonstrating
its longer term sustainability, one of the most important crite-
ria against which the Key Centre will be judged.
Photovoltaic Engineering and the
development of a range of double
degree programs at undergraduate
level, will complement the ongoing
development of the new Bachelor of
Engineering.
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG I N T R O D U C T I O N
K5 �� K4
An important aim of each Key
Centre is to become a national
focus in it's particular area. For the
Key Centre for Photovoltaic
Engineering, this has encouraged
the establishment of collaborative
programs with other institutions,
organizations and industry. Collab-
orations have also been established
with overseas institutions and
organizations, although in general
these have been initiated by over-
seas organizations wanting to
benefit from Key Centre educa-
tional programs, expertise and/or
technology.
In the research area, all programs
have been industry initiated and
self-funding. It was made clear
when establishing the Key Centre
for Photovoltaic Engineering that
it's ARC funds would not be used
to fund research projects.
Nevertheless, the Key Centre has
successfully established several
industry collaborative research
programs funded by the industry
partner and in a couple of cases,
through ARC SPIRT grants.
The primary new initiatives of
this new Key Centre are in the
educational area. In particular, the
Key Centre is developing the
world’s first Bachelor of Engin-
eering in Photovoltaics and Solar
Energy. This is in response to
rapid growth in the industry in
recent years in excess of 30% per
annum, with the expectation that
this rate of growth will continue
for many years to come. As
expected, substantial levels of job
creation, particularly for appro-
priately trained engineers, are tak-
ing place throughout the renew-
able energy sector as a whole and
in particular within the photo-
voltaics industry. There appears
to be a very important future for
photovoltaic engineering.
Growth inPhotovoltaic andRenewable EnergyEngineering
WWhhaatt iiss PPhhoottoovvoollttaaiicc ((PPVV))EEnnggiinneeeerriinngg??
Photovoltaic Engineering focuses
on the manufacture and use of
photovoltaic modules and the
implementation of photovoltaic
one million houses for America.
Governments have demonstrated
their willingness to offer whatever
subsidies are necessary to ensure
these targets are met, particularly
in Europe and Japan.
In response to the booming PV
market, many manufacturers glob-
ally are rapidly increasing their
production capacity. Australian
manufacturers currently enjoy
almost 8% of the international
market, a figure that is expected to
increase in the future as state of
the art Australian technology
enters the market place. The
explosive demand for photo-
voltaics causes dramatic drops in
the cost of PV, which in turn pro-
motes additional growth. Figure
K3 shows historically the relation-
ship between the cost of photo-
voltaic modules and the corre-
sponding installed capacity or
market size. If this straight line
relationship continues as expect-
ed, then the reduction of the pho-
tovoltaic module price to its
apparent long term potential of
under $1 per Watt, could lead to
photovoltaic markets expanding
by more than a factor of 1,000.
International studies predict an
expansion of more than a factor
of 20 over the coming decade.
results of a study that predicted
30,000-80,000 new jobs would be
created in Austria alone in the pho-
tovoltaic sector by 2010. Similar
types of studies have been carried
out throughout the world, with
similar types of conclusions drawn
with regard to job creation. Using
data from these studies, Figure K4
shows that the likely international
job creation in the photovoltaics
sector by the year 2004, when the
first photovoltaic engineers gradu-
ate from UNSW, is about 50,000-
60,000 new jobs. Many of these
will be engineering positions.
JJoobb CCrreeaattiioonn aanndd EEdduuccaattiioonnaallRReeqquuiirreemmeennttss
The rapidly expanding photo-
voltaic industry creates the need
for photovoltaic engineers. Inter-
national studies indicate that
approximately 50 new jobs are
created for each 1 MW per annum
increase in production capacity of
photovoltaics. Based on present
growth rates in the industry, this
indicates that hundreds of thou-
sands of jobs will be created in
the photovoltaic sector alone dur-
ing the next decade, with about
20% of these in manufacturing.
IInntteerrnnaattiioonnaall JJoobb GGrroowwtthh ––WWhhaatt ddoo tthhee EExxppeerrttss SSaayy??
The most detailed job study is part
of a 1996 European Green Paper
adopted by the European Par-
liament and subsequently expand-
ed into a White Paper. This paper
cites a study showing that for the
photovoltaic sector alone, well in
excess of 100,000 jobs will be cre-
ated in Europe by 2010, while for
the broader renewable energy sec-
tor, hundreds of thousands of
jobs will be created during the
same time frame. In addition, in
the late 1990’s, the Austrian
Federal Minister for the Envi-
ronment publicly announced the
systems for the purposes of pow-
ering virtually any electrical load. It
covers a broad range of engineer-
ing tasks and disciplines, but it can
be summarised into five main
areas. These are:
� Device and system research
and development;
� Manufacturing, quality control
and reliability;
� PV system design (computer
based), modelling, integration,
analysis, implementation, fault
diagnosis and monitoring;
� Policy, financing, marketing,
management, consulting, train-
ing and education;
� Using the full range of renew-
able energy technologies in-
cluding alternate energy tech-
nologies (such as wind, biomass,
and solar thermal), solar archi-
tecture, energy efficient building
design and sustainable energy.
TThhee BBoooommiinngg PPhhoottoovvoollttaaiicc IInndduussttrryy
The PV industry has been growing
at a rate of 30% per annum, which
is faster than the computer
or telecommunications industries.
Figure K2 shows the explosive
nature of the PV industry growth.
These soaring growth rates are
predicted to continue as the new
market, grid-connected photo-
voltaics on residential houses,
expands. Government initiated
plans throughout the world have
already been formulated for the
implementation of at least three
million additional houses to be
powered by solar cells during the
first decade of the new millenni-
um. One and a half million houses
are targeted for Japan, one million
houses for Europe, and a further
IntroductionIntroductionThe University of New South Wales was awarded a Key Centre
for Teaching and Research in Photovoltaic Engineering which
commenced in January, 1999. This Key Centre has been estab-
lished as part of the Australian Research Council’s Key Centres
Scheme, and was one of only eight such Key Centres awarded
Australia-wide across all disciplines.
FIGURE K1: NEW
DEGREE BROCHURE.
FIGURE K2: MASSIVE GROWTH
IN ANNUAL PHOTOVOLTAIC
PRODUCTION
FIGURE K3: SELLING PRICE FOR
PHOTOVOLTAICS AS A FUNCTION
OF MARKET SIZE.
FIGURE K4: ANTICIPATED JOB
CREATION BY THE YEAR 2004
AS A FUNCTION OF ANNUAL
GROWTH RATE FOR THE
PHOTOVOLTAIC INDUSTRY.
WWhhaatt eedduuccaattiioonn aanndd ttrraaiinniinngg aarree nneeeeddeedd ffoorr tthheessee jjoobbss??
Unfortunately, as identified by many
manufacturers and end users, limit-
ed educational opportunities exist
for engineers to gain the necessary
training and qualifications to suit
the needs of the rapidly expanding
photovoltaics and renewable energy
sectors. For example, Western
Power, who owns all the electricity
grids in Western Australian, has
found it impossible to find appro-
priately trained engineers for its rap-
idly expanding use of renewable
energy technologies such as wind
I N T R O D U C T I O N
K7 �
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K6
power and photovoltaics. Western
Power has consequently taken the
initiative to fund the establishment
of a new undergraduate engineer-
ing program at Murdoch University
to specifically address this need. In
NSW, photovoltaic manufacturing
is particularly strong with almost all
of Australia’s manufacturing capac-
ity being based in Sydney. A similar
situation exists whereby appropri-
ately trained engineers are unavail-
able. The local photovoltaics indus-
try has been drawing heavily on
graduates from Electrical Engin-
eering at the University of New
South Wales and then subsequently
facilitating additional training for
these graduates to equip them as
photovoltaic engineers. Of the 137
graduates from Electrical Engin-
eering in 1998 at UNSW, 3 of the
students from the top 5 ranking,
entered the local photovoltaics
industry.
PPhhoottoovvoollttaaiicc JJoobbss iinn NNSSWW
A media release in July, 1999
from the Minister for Energy, Mr.
Kim Yeadon, announced that the
growth in the Green Energy
Sector (which includes all aspects
of photovoltaic engineering
including the use of all renewable
energy technologies and energy
efficient building design), is out-
stripping that of the booming
Information Technology industry
in the state of NSW. In addition,
he announced that the expected
job creation in NSW in the
Green Energy Sector for the fol-
lowing 12 month period would
be approximately 1,200 new posi-
tions. Perhaps just as importantly,
the same study revealed that
1,000 new jobs have already been
created in the sector in the previ-
ous 2-3 years.
that 50% of its entire business is
likely to be through renewable
energy technologies by 2050.
Similarly, BP Solar has been
expanding its photovoltaic produc-
tion capacity by a factor of 2 each
year and has announced that it will
grow to a $1 billion per year busi-
ness by 2007.
WWhhiicchh CCoommppaanniieess EEmmppllooyyPPhhoottoovvoollttaaiicc EEnnggiinneeeerrss??
At present, the major companies
employing photovoltaic engineers
include manufacturers, research
organisations, system design and
integration companies, electricity
utilities (such as Pacific Power,
ACT Electricity and Water and
Western Power), and major end
users of products including, for
example, communications compa-
nies such as Telstra. However, the
number of companies employing
photovoltaic engineers is increas-
ing. Many more companies are
recognising the importance of
these energy sources and hence for
appropriately trained engineers.
This demand is being fuelled by
both the environmentally friendly
nature of renewable energy tech-
nologies and also by the technical
advantages inherent in photo-
voltaics. Even major oil companies
are investing heavily in solar tech-
nology, indicating the need for
photovoltaic and renewable energy
engineers. For example, Shell Oil
Company has publicly announced
FIGURE K5: RENEWABLE ENERGY SYSTEMS BASED
ON PHOTOVOLTAICS AND WIND CONVERTERS.
FIGURE K6: SOLAR POWERED
STREET LIGHT.
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG I N T R O D U C T I O N
K9 �� K8
Key Centre StaffWith the establishment of the Key
Centre, many of the existing staff
from the photovoltaics group at
UNSW took on positions within
the Key Centre. Of particular
importance, Professor Stuart
Wenham became the Director of
the Key Centre, Dr Christiana
Honsberg has been appointed as
Director of Academic Studies,
Mark Silver retains his role as
Business and Technology Manager,
and Rob Largent has been appoint-
ed as Educational Co-ordinator.
The academic staff involved in the
photovoltaics area, formerly part of
the School of Electrical Engin-
eering, have also transferred to the
new budget unit created with the
establishment of the Key Centre.
In the research area, the originally
proposed management structure
has been slightly modified. The
new structure involves appointing
managers for each individual col-
laborative research project with
industry, with each of these man-
agers reporting directly to the Key
Centre Director. This change has
enabled Professor Martin Green to
take on directorship of the new
Special Research Centre which
commenced in the year 2000.
NNeeww AAccaaddeemmiicc SSttaaffff
With the commencement of the
Key Centre, two high profile aca-
demic staff appointments were
made. Dr Armin Aberle, widely
recognized as one of Europe’s
leading photovoltaic researchers
in the crystalline silicon area,
joined UNSW in late 1998 and
the Key Centre in January, 1999.
Dr Aberle was formerly the
Head of the Photovoltaic De-
partment at the Institute for
NNeeww AAddmmiinniissttrraattiivvee OOffffiicceeMMaannaaggeerr
Ms Lisa Cahill joined the Key Centre
as Administrative Office Manager in
June, 1999. Ms Cahill has had many
years of experience working in the
Electrical Engineering School office
including a period as Administration
Officer. Ms Cahill is taking responsi-
bility for the administration and
implementation of the new educa-
tional programs initiated by the Key
Centre with most emphasis to date
being on the development, imple-
mentation and promotion of the
new Bachelor of Engineering in
Photovoltaics and Solar Energy.
GoverningCommitteesThe Key Centre has two govern-
ing committees, a Management
Committee that deals with the
day to day running of the
Centre’s activities, and an
Advisory Committee comprising
industry leaders, end-users and
representatives from other insti-
tutions with related interests.
The Advisory Committee pro-
vides advice and direction for the
Management Committee.
AstroPower (Professor Allen Barnett,
Director)
BP Solarex Pty Ltd (David Jordan,
Director, Engineering Best Practice)
Ceramic Fuel Cells Ltd (Dr Bruce
Godfrey, Managing Director)
Pacific Power (Mr Robert Lang,
General Manager/Development)
University Academics
The University of NSW (Professor
Mark Wainwright, Dean,
Engineering)
Australian National University
(Dr Andres Cuevas)
Murdoch University (Professor Phil
Jennings, Dean, Science and
Engineering)
Delaware University (Professor Allen
Barnett)
MMaannaaggeemmeenntt CCoommmmiitttteeee
The management committee meets
fortnightly and comprises the aca-
demic staff members of the Key
Centre, the administrative office
manager, the education officer, the
business manager and the Key
Centre Director. The Dean of
Engineering is also considered to be
a member of the Management
Committee although instead of
attending the fortnightly meetings, he
has regular separate meetings with
the Key Centre Director.
AAddvviissoorryy CCoommmmiitttteeee
The advisory committee meets
annually, although correspondence
with individual members takes
place on a more regular basis. The
emphasis during the last twelve
months has been on the formation
of this committee with the mem-
bership including industry leaders,
manufacturers, academics from
other institutions and representa-
tives of end-users. The member-
ship includes the following:
MMaajjoorr IInndduussttrryyRReepprreesseennttaattiivveess
Pacific Solar Pty Ltd (David Hogg,
Managing Director)
Solar Energy Research (ISFH) in
Germany. In January, 2000, Dr
Aberle was relieved of all teach-
ing responsibilities to the Centre
for Photovoltaic Engineering for
a period of three years to facili-
tate his appointment as Deputy
Director to the new Special
Research Centre.
The other new academic appoint-
ment was Dr Jeff Cotter, previ-
ously awarded a Postdoctoral
Fellowship in Photovoltaics at
UNSW. The quality and interna-
tional competitiveness of Dr
Cotter’s research during his fel-
lowship has been recognised by
his appointment to the academic
staff shortly after the establish-
ment of the Key Centre. Prior to
joining UNSW, Dr Cotter has had
extensive experience in industry
following several years of
employment by AstroPower, one
of the largest photovoltaic manu-
facturers in the USA. In addition
to the industrial experience, Dr
Cotter has a particularly strong
academic record as demonstrated
by his prestigious award for aca-
demic excellence for his perform-
ance in UNSW postgraduate
courses.
DR ARMIN ABERLE
ACADEMIC STAFF
DR JEFF COTTER
ACADEMIC STAFF
MR ROBERT LARGENT
EDUCATION CO-ORDINATOR
DR CHRISTIANA HONSBERG
DIRECTOR OF
ACADEMIC STUDIES
MS LISA CAHILL
ADMINISTRATIVE OFFICE
MANAGER
The University of New South Wales
(Associate Professor Hugh Outhred).
Representatives of the end-users
and other organizations
Solar Energy Industries Association of
Australia (Geoff Stapleton, President
of the NSW Branch)
Sustainable Energy Development
Authority of NSW (Executive
Director)
Australian CRC for Renewable Energy
(Professor Phil Jennings)
Australian CRC for Renewable Energy
(Dr Bruce Godfrey, Chairman of the
Board)
EnergyAustralia (Neil Gordon,
Manager, Sustainable Energy Branch)
Integral Energy (Geoff Stapleton,
Sustainable Energy Branch)
MEMBERS OF THE GROOVE DIFFUSION BAND AFTER PACKING
THE HOUSE AT THE CAT & FIDDLE HOTEL, BALMAIN.
ONLY ENGINEERS WOULD NAME A BAND AFTER THEIR RESEARCH PROCESSES!
1I N T R O D U C T I O N
K11 �
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K10
AutonomousCentreA requirement for the Key
Centre has been its establish-
ment as an autonomous centre
within the University system
with access to the funds it gen-
erates. The University has hon-
oured this commitment, facili-
tating the establishment of a
budget unit independently of
the School of Electrical
Engineering, called the Centre
for Photovoltaic Engineering.
The granting of independence
to the photovoltaic group has
required a lengthy reconciliation
period which was finally con-
cluded during January, 2000.
The new arrangements provide
the Key Centre with access to
all the funds it generates includ-
ing EFTSU’s and research quan-
tum. This arrangement provides
the Key Centre with opportuni-
ty to demonstrate its sustain-
ability as required by the Key
Centre’s Scheme.
1E D U C A T I O N
K13 �
and 12 high school students and capi-
talizing on the involvement with the
World Solar Challenge and also
Sunsprint which involves model solar
car racing for high schools. Other
more conventional forms of promo-
tion have included the production and
distribution of brochures and the pro-
vision of laboratory tours for visiting
high school groups as well as the pub-
lishing of related material at confer-
ences and in journals. A less orthodox
form of promotion has taken place
through the development of the
Virtual World Solar Challenge, an edu-
cational game developed as a teaching
tool for the new degree, which has
been made available on the Centre’s
website for access via the internet. The
Centre has sponsored a corresponding
competition for high school partici-
pants, with more than 7,000 entries
achieved.
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K12
Rapid growth in the renewable
energy sector and in particular
within the photovoltaics industry,
has led to a shortage of appropri-
ately trained engineers. Based on
several international studies, this
shortage is expected to increase
in coming years as the industry
continues to rapidly expand. The
lack of availability of appropri-
ately trained engineers is being
exacerbated by time delays associ-
ated with implementing new edu-
cation and training programs. The
new Bachelor of Engineering is a
four year program which com-
menced in the year 2000. The last
year has been important for
curriculum/course development
in addition to gaining the neces-
sary approvals at school, faculty,
academic board and finally
University Council levels. Formal
approval for the new program has
now been granted. A range of
advanced teaching tools, re-
sources and techniques have been
developed such as the new multi-
media interactive CD-ROM,
developed primarily for the
purposes of two of the new
courses within the new engineer-
ing program.
A key feature of the new program
is the opportunity provided for
each student to choose a second
area of specialization. Ten options
have already been developed
encompassing most engineering
areas although students are given
the opportunity to develop their
own unique strand that encom-
passes their second area of inter-
est. It is anticipated that many of
these alternative areas will be able
to be expanded into a double
degree program through an extra
year of study if desired by the stu-
dent. Throughout the program,
considerable emphasis is placed on
allowing the student to gain hands-
on experience, particularly with
designing and working with photo-
voltaic systems through project
and laboratory work. Major proj-
ects commence in the second year
of the program.
Considerable promotion of the
new Bachelor of Engineering in
Photovoltaics and Solar Energy
has taken place during the last year.
This promotion has included the
development of a multimedia CD-
ROM which gives an overview of
the program, related industries, job
opportunities, research activities in
the area, the academic staff devel-
oping and teaching the program,
and so on. Distribution of the CD-
ROM includes all high schools
throughout Australia. Other pro-
motion includes several informa-
tion days at UNSW, demonstra-
tions and tours during the
University open-day, several public
lectures, a symposium for year 11
EducationEducation
SSOOLLAAAA1133664422
PPHHOOTTOOVVOOLLTTAAIICCSS AANNDD SSOOLLAARR EENNEERRGGYY –– FFUULLLL-TTIIMMEE PPRROOGGRRAAMM
BBAACCHHEELLOORR OOFF EENNGGIINNEEEERRIINNGG
BBEE
YYeeaarr 11 HHPPWW HHPPWW
SS11 SS22 UUCC
SOLA1050 Introduction to Solar Energy,
Photovoltaics & Computing 4 3 9
SOLA1060 Chemistry for Semiconductor Devices 0 3 3
ELEC1011 Electrical Engineering 1 6 0 6
ELEC1041 Digital Circuits 0 4 6
*MATH1141 Higher Mathematics 1A 6 0 6
*MATH1241 Higher Mathematics 1B 0 6 6
PHYS1131 Physics 1A 6 0 6
PHYS1231 Physics 1B 0 6 6
Total 22 22 48
*MATH1141 and *MATH1241 may be taken at the ordinary level.
YYeeaarr 22 HHPPWW HHPPWW
SS11 SS22 UUCC
Selected Strand 5 5 12
SOLA2051 Project in Photovoltaics and Solar Energy 4 3 9
SOLA2020 Photovoltaic Technology and
Manufacturing 4 0 6
ELEC2042 Real Time Instrumentation 0 3 3
MATH2849 Statistics EE 0 3 3
MATH2509 Linear Algebra 0 3 3
SOLA2050 Sustainable Energy 2.5 0 3
SOLA2060 Introduction to Electronic Devices 0 2.5 3
General Education Electives 4 0 6
Total 19.5 19.5 48
YYeeaarr 33 HHPPWW HHPPWW
SS11 SS22 UUCC
Professional Electives 4 8 18
Selected Strand (continued) 5 0 6
SOLA3055 Renewable Energy Engineering 2.5 0 3
SOLA3540 Applied Photovoltaics 4 0 6
SOLA3507 Solar Cells and Systems 0 4 6
SOLA3054 Renewable Energy Product
Reliability 2.5 0 3
General Education 0 4 6
Total 18 16 48
YYeeaarr 44 HHPPWW HHPPWW
SS11 SS22 UUCC
Professional Electives 4 4 12
ELEC4010 Introduction to Management for Electrical
Engineers 3 0 3
ELEC4011 Ethics and Electrical Engineering Practice 0 2 3
SOLA4010 Building Integrated Photovoltaics 2.5 0 3
SOLA4012 Grid Connected Photovoltaic Systems 4 0 6
SOLA4013 Current Issues in Photovoltaics 0 2.5 3
SOLA4910 Thesis Part A 5 0 6
SOLA4911 Thesis Part B 0 10 12
Total 18.5 18.5 48
New Bachelor of Engineering inPhotovoltaics and Solar Energy
OOvveerrvviieeww
One of the primary new initiatives of the Key Centre for
Photovoltaic Engineering is the development and establish-
ment of the world’s first new Bachelor of Engineering in
Photovoltaics and Solar Energy.
FIGURE K8: NEW CD-ROM ON PHOTOVOLTAICS: DEVICES,
SYSTEMS AND APPLICATIONS: VOLUME 1, DEVELOPED FOR
THE NEW TEACHING PROGRAMS.
FIGURE K9: MULTIMEDIA
CD-ROM DEVELOPED TO PRO-
VIDE INFORMATION ABOUT THE
NEW BE IN PHOTOVOLTAICS
AND SOLAR ENERGY.
FIGURE K10: MODEL SOLAR CARS
LINING UP TO COMPETE IN THE
SUNSPRINT COMPETITION.
FIGURE K11: MODEL SOLAR CAR
DESIGNED FOR THE SUNSPRINT
COMPETITION.
PPrrooggrraamm OOuuttlliinnee
The program approved by the University’s academic board and the University
Council is summarized as follows:
E D U C A T I O N
K15 �
prises 18 Units of Credit (UC)
with the opportunity to subse-
quently select additional Elec-
tives in the corresponding area in
the final two years. The ten
strands available are listed with
the subject(s) comprising the last
6 Units of Credit to be taken in
year 3.
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K14
Years 2 & 3 Strand Options
Students have the opportunity to
select one of eight possible strands
to complement their education in
Photovoltaics and Solar Energy
Engineering, or develop their own
unique strand. Each strand com-
PPrrooffeessssiioonnaall EElleeccttiivveess ffoorr YYeeaarrss 33 && 44
Because of timetable clashes not all combinations of subjects are possible.
HHPPWW HHPPWW
SS11 SS22 UUCC
SOLA5508 High Efficiency Silicon Solar Cells 0 2.5 3
SOLA5011 Solar Cells: Operating Principles and
Technology 0 4 6
SOLA5053 Wind Energy Converters 0 4 6
SOLA5052 Biomass 4 0 6
SOLA5051 Life Cycle Assessment 2 0 3
SOLA5050 Renewable Energy Policy and
International Programs 2 0 3
MECH4720 Solar Energy 0 4 6
MECH4740 Thermal Power Plants 4 0 6
YYeeaarrss 22 && 33 SSttrraanndd OOppttiioonnss
SSttrraanndd 11 CCoommppuuttiinngg aanndd CCoonnttrrooll HHPPWW HHPPWW
SS11 SS22 UUCC
COMP1011 Computing 1A 6 0 6
COMP1021 Computing 1B 0 6 6
COMP2011 Data Organisation 5 0 6
SSttrraanndd 22 EElleeccttrroonniiccss HHPPWW HHPPWW
SS11 SS22 UUCC
ELEC2031 Circuits and Systems 3 3 6
ELEC3006 Electronics A 6 0 6
ELEC3016 Electronics B 0 5 6
or
ELEC3017 Electrical Engineering Design 0 5 6
SSttrraanndd 33 EElleeccttrriicc EEnneerrggyy HHPPWW HHPPWW
SS11 SS22 UUCC
MATH2011 Several Variable Calculus 4 0 6
PHYS2939 Electromagnetism 3 0 3
ELEC2015 Electromagnetic Applications 0 3 3
ELEC3005 Electrical Energy 1 5 0 6
SSttrraanndd 44 CCoommmmuunniiccaattiioonnss HHPPWW HHPPWW
SS11 SS22 UUCC
ELEC2031 Circuits and Systems 3 3 6
MATH2620 Complex Analysis 0 2.5 3
MATH3150 Transform Methods 0 3 3
TELE3013 Telecommunications Systems 1 5 0 6
SSttrraanndd 55 MMaatthheemmaattiiccss HHPPWW HHPPWW
SS11 SS22 UUCC
MATH2011 Several Variable Calculus 4 0 6
MATH2620 Complex Analysis 0 2.5 3
MATH1090 Discrete Mathematics 3 0 3
MATH3141 Mathematical Methods EE 0 4 6
SSttrraanndd 66 MMeecchhaanniiccaall EEnnggiinneeeerriinngg HHPPWW HHPPWW
\\SS11 SS22 UUCC
MECH2601 Fluid Mechanics and Thermodynamics A 4 0 6
MECH2602 Fluid Mechanics and Thermodynamics B 0 4 6
MECH3601 Thermofluid System Design 3 0 3
MECH3602 Advanced Thermodynamics 0 3 3
SSttrraanndd 77 CCiivviill EEnnggiinneeeerriinngg HHPPWW HHPPWW
SS11 SS22 UUCC
CVEN1023 Statics 3 0 4
CVEN1026 Mechanics of Solids 0 3 4
CVEN2023 Engineering Materials 3 0 3
CVEN2322 Introduction to Structure Engineering 1 0 6 6
CVEN3126 Engineering Management 1 0 3 3
SSttrraanndd 88 CChheemmiiccaall EEnnggiinneeeerriinngg HHPPWW HHPPWW
SS11 SS22 UUCC
CEIC0010 Mass Transfer and Material Balance 2 2 4
INDC3010 Thermodynamics 3 0 3
CHEN2030 Heat Transfer 0 3 3
CEIC2040 Applied Electrochemical and Surface
Processes 1.5 0 2
INDC3031 Experimental Design 2 1 3
INDC3041 Corrosion in the Chemical Industry 0 3 3
FIGURE K12: FABRICATION OF
WORLD RECORD SOLAR CELLS IN
THE UNSW LABORATORIES.
VISITS TO THESE LABORATORIES
ARE POPULAR WITH HIGH
SCHOOL STUDENTS.
FIGURE K13: THE HONDA
SOLAR CAR POWERED BY SOLAR
CELLS FABRICATED IN THE
UNSW LABORATORIES. THIS CAR
HOLDS THE RACE RECORD FOR
THE WORLD SOLAR CHALLENGE.
FIGURE K14: STUDENTS LEARN ABOUT GENERATING
ELECTRICITY FROM WIND CONVERTERS.
FIGURE K15: COMMERCIAL SOLAR CELL PRODUCTION LINE.
FIGURE K16: GRID CONNECTED
ROOF TOP PHOTOVOLTAIC
SYSTEM.
1E D U C A T I O N
K17 �
The second year major project will
in general be more structured than
the final year thesis and can involve
group or individual projects. One
exciting aspect is that all students
will submit all of their project
reports as a formatted HTML doc-
ument, which will then be promi-
nently displayed on-line as a part
of the Key Centre's world-wide-
web site. Not all projects will run
each year. Possible projects cur-
rently being planned include:
students and supervisors will live
within the local village to gain an
appreciation of local life style, cus-
toms and culture. Experts will test
the installed systems in conjunc-
tion with the students prior to their
return to Sydney where a report is
to be written to complete the proj-
ect requirements.
Solar Car Project
The solar car project has proved to
be very popular with engineering
students for many years. The overall
aim is to design, develop, build, test
and eventually race such a solar car.
A wide range of individual projects
are available in this area. This project
is perhaps a good example of how
engineers from a broad range of
backgrounds need to work togeth-
er to facilitate the achievement of
overall goals. It also highlights the
importance of photovoltaic engi-
neers gaining a second area of spe-
cialization to bring cross-discipli-
nary expertise to bear on the proj-
ect. During the last year, students
System Training and
Installation in Nepal
Travelling to Nepal or another part
of the developing world to study
and gain hands-on experience in
the use of renewable energy tech-
nologies is an option made avail-
able to students. In particular, stu-
dents will be trained by experts in
the use of photovoltaic systems,
their design, installation and on-
going maintenance requirements.
Students will then proceed to
install their own system on one of
the local dwellings in one of the
villages in Nepal, comprising a
photovoltaic panel, battery backup,
a system controller, appropriate
mounting structures and small
electrical loads such as fluorescent
lights. During their stay in Nepal,
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K16
Electives can also be chosen from
the subjects listed as electives
for Electrical Engineering, Mech-
anical Engineering, Civil Engin-
eering, Environmental Engineering,
Computer Science and Engineering
and Chemical Engineering for
which appropriate pre-requisite
requirements have been satisfied
and which conform to the credit
point requirements.
DDoouubbllee DDeeggrreeeess iinn tthheeSSeeccoonndd AArreeaa ooff SSppeecciiaalliizzaattiioonn
As indicated above, all students
choose a strand in the second year
of the program that gives tuition
and specialization in a second area.
At the completion of the strand,
students will have gained 18 credit
points which in many cases can be
used as a contribution towards
gaining the necessary 60 extra cred-
it points in a second area to gain a
double degree. In general, the
achievement of a double degree in
an approved program will require
an extra fifth year of study.
Ten strand options have already
been developed, although freedom
is given to students to develop
their own strand options through
consultation with staff from the
school responsible for the second
area. These strand options appear
to be quite popular with the new
students who commenced the
program in the year 2000.
EEnnrroollllmmeennttss
The quota for the new program was
set at 30 for the year 2000. High
demand, however, has led to the
enrolment of 41 students for the first
year of the program, with most stu-
dents having University Admission
Index (UAI) scores well above 90
(see Figure K18).
UUnnddeerrggrraadduuaattee PPrroojjeeccttss
Major projects are taken during the
second and fourth years of the
program. The final year thesis can
be taken in virtually any area
encompassed by the Photovoltaics
and Renewable Energy sectors. In
particular, the world class photo-
voltaic laboratories are well suited
to thesis work in the device area,
although many students may prefer
thesis topics encompassing sys-
tem design, applications, device
and system modelling, environ-
mental issues, balance of system
components, control electronics,
policy, reliability issues, manufac-
turing, the range of renewable
energy technologies, life expec-
tancy, and so on.
FIGURE K17: ELECTRICITY
GENERATION FROM PHOTOVOLTAICS
AND WIND GENERATORS CAN WORK
WELL IN MOST COUNTRIES INCLUD-
ING THE DEVELOPING WORLD.
FIGURE K18: HIGH QUALITY STUDENTS ATTTRACTED INTO THE NEW
BE IN PHOTOVOLTAICS AND SOLAR ENERGY WITH MOST STUDENTS
HAVING UAI SCORES ABOVE 90.
FIGURE K19: OLD FASHIONED
WIND GENERATOR.
FIGURE K20: APPLICATIONS SUCH AS SOLAR POWERED VENDING
MACHINES MAKE GOOD STUDENT PROJECTS.
FIGURE K21: STUDENT PROJECTS IN
DEVELOPING COUNTRIES SUCH AS
NEPAL, APPEAR TO BE PARTICULARLY
POPULAR WITH STUDENTS IN THE BE
IN PHOTOVOLTAICS AND SOLAR
ENERGY PROGRAM. PHOTOVOLTAICS
AND RENEWABLE ENERGY SYSTEMS ARE
PARTICULARLY IMPORTANT FOR THE
DEVELOPING WORLD.
1E D U C A T I O N
K19 �
below is an example of this type
of project.
Local Renewable
Energy Systems
Students are able to get involved
with various local renewable
energy systems. One example is
the photovoltaic powered light-
house on Montague Island. This
installation was designed and
installed by engineers from the
Centre for Photovoltaic Engin-
Sustainable Energy Development
Authority (SEDA) in Sydney also
has a range of projects involving
renewable energy technologies,
energy efficiency, sustainable engi-
neering and environmental issues
such as greenhouse gas emission
reduction. SEDA has indicated
their willingness to have students
from the new BE in Photovoltaics
and Solar Energy program
involved in these types of projects.
Solar Cell Production
Line Projects
Possible projects exist in conjunc-
tion with manufacturers who are
licensees of UNSW photovoltaic
technology. These projects could
potentially take a range of forms
depending on the interests of the
student and the needs of the compa-
nies. Licensees of UNSW technolo-
gy exist in many of the major coun-
tries around the world.
eering and provides a good test
bed for on-going system testing,
analysis, modelling and optimiza-
tion. Data loggers are to be
installed to facilitate easy access to
data relating to system perform-
ance. Another example is the wind
generator at Malabar. Negotiations
are presently under way to provide
access for students to the wind
generator at Malabar for the pur-
poses of carrying out a range of
projects with this technology. The
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K18
prepared for, and then raced in, the
World Solar Challenge from
Darwin to Adelaide and then the
Sunrace from Sydney to Mel-
bourne. In the latter of these races,
the students were placed second
until the closing stages of the race
when mechanical failure forced
their withdrawal. In the World
Solar Challenge, the Aurora car
won the race using solar cells fabri-
cated in the laboratories of the
Centre for Photovoltaic Engin-
eering at UNSW.
Grid-connected Photovoltaic
Roof-top Systems
Pacific Solar has initiated a program
for installing photovoltaic rooftop
systems throughout Sydney. More
than 3 million photovoltaic powered
houses have already been planned
internationally for implementation
over the next decade. Students
choosing this as their project area will
have the opportunity to study first
hand the design of these systems at
Pacific Solar and then attend and
view the installation of such systems
by experts. Project work will proba-
bly also include testing and monitor-
ing the system performance follow-
ing installation. These systems are all
grid-connected, using the AC mod-
ule concept whereby each individual
photovoltaic module has its own
integral inverter for interfacing to the
electricity grid. Pacific Solar is plan-
ning to install a manufacturing facili-
ty in Sydney capable of producing
more than 130,000 of these modules
each year. The Government has
announced a 50% subsidy for such
systems to ensure rapid market
growth.
Model Solar Car Racing
Sunsprint is a model solar car race
for high school teams. Each school
forms its own team and designs its
own model solar car. Student proj-
ects in this area can include:
involvement with organizing and
running the event; web-based
delivery of results including the
use of movie clips and digital pho-
tographs made available via the
internet; or even co-ordinating the
activities of a given team such as
the high school previously attend-
ed by the particular student.
Development of Multimedia
Presentations
Students interested in carrying out
research in any of the renewable
energy areas are given the opportu-
nity to choose a topic, carry out the
research and then prepare a multi-
media presentation on the topic.
Students will be trained to devel-
op the skills necessary for pro-
ducing multimedia presentations
from their research material,
including web page design,
HTML and DHTML coding,
Macromedia Director anima-
tions, Java and Javascript pro-
gramming, etc. The Virtual
World Solar Challenge described
FIGURE K22: DESIGNING, BUILD-
ING AND RACING SOLAR CARS IS
ANOTHER PARTICULARLY POPU-
LAR PROJECT WITH STUDENTS.
FIGURE K23: THE AURORA
SOLAR CAR WITH SOLAR CELLS
FABRICATED IN THE UNSW
LABORATORIES, WON THE 1999
WORLD SOLAR CHALLENGE.
FIGURE K24: ROOF TOP PHOTOVOLTAIC SYSTEM INSTALLED BY PACIFIC
SOLAR IN SYDNEY. INTERESTED STUDENTS MAY HAVE THE OPPORTUNITY
TO WORK WITH SUCH A SYSTEM.
FIGURE K25: SEVERAL STUDENT PROJECTS RELATE TO THE MODEL
SOLAR CAR RACING ACTIVITIES ASSOCIATED WITH THE SUNSPRINT
COMPETITION FOR HIGH-SCHOOL STUDENTS.
FIGURE K26: IT IS AMAZING WHAT CAN BE USED
TO MAKE A MODEL SOLAR CAR!
FIGURE K27: VARIOUS STUDENT
PROJECTS ARE EXPECTED TO
BE OFFERED IN CONJUNCTION
WITH THE WIND GENERATOR
AT MALABAR.
1E D U C A T I O N
K21 �
New Master of EngineeringScience inPhotovoltaicEngineering
It is currently possible to enroll in
a Master of Engineering Science in
Electrical Engineering which
includes several photovoltaic
device and application based sub-
jects. A new Master of Engi-
neering Science program is cur-
rently being planned and devel-
oped in photovoltaic engineering
which will include a range of new
subjects developed in conjunction
with material and teaching aids
developed for the new Bachelor of
Engineering. The new Master of
Engineering Science program is
expected to be approved by the
Academic Board of UNSW and
University Council over the next
twelve months.
IInntteerraaccttiivvee TTeeaacchhiinnggRReessoouurrcceess
Overview
The increasing prevalence of com-
puters offers many chances to
increase and improve learning
opportunities in the photovoltaic
area though the development of
interactive teaching resources.
ous forms, including "active equa-
tions", interactive graphs or simu-
lations. A teaching grant to devel-
op these concepts based on cog-
nitive load theory was granted
from the CUTSD recently. Based
on this grant, an interactive CD-
ROM, Photovoltaics Devices, Systems
& Applications: Volume I was
developed and published.
An additional important area in the
development of effective teaching
resources is the development of
"simulated laboratories" or "simu-
lated systems" that also invoke
similarities to a "mental game".
Simulated laboratories or systems
have often been cited as a means to
more effectively allow students to
perform simulated experiments.
However, a key limitation in these
approaches has been the absence
of "random" fluctuations that test
students’ understanding and devel-
op their analysis skills. The
"Fantasy World Solar Challenge"
incorporates both elements of a
computer game and random
events into a single, entertaining
teaching package.
IInntteerraaccttiivvee CCDD-RROOMM::
Photovoltaics Devices,Systems & Applications:Volume I
Project Leader:
Dr C. B. Honsberg
The PVCDROM Photovoltaics:
Devices, Systems & Applications:
Volume I is an interactive CD-ROM
that explains the operation, design
and technology of photovoltaic
devices and modules. The CD-
ROM is an ideal introduction to
the solar cell area, with particular
relevance to industry and educa-
tion. It is used in the Applied
Increasing the education opportu-
nities in photovoltaics is particular-
ly important because photovoltaics
is rapidly expanding and it is also
very diverse, both in terms of
where it is geographically sited
(and hence where people wish to
learn about it) and also in the range
of applications.
The development of interactive
teaching resources offers many
benefits to students in photo-
voltaics. For example, interactive,
multimedia animations or simula-
tions improve educational out-
comes by allowing users to visu-
alise important abstract or mathe-
matical concepts. These programs
also take education a step further
by encouraging users to experi-
ment with equations and observe
the relationships between inputs
and outputs. Such an experimental
approach allows the user to devel-
op their own mental model of a
concept, and assists in the stu-
dents’ understanding and ability to
apply these concepts. These inter-
active components may take vari-
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K20
FIGURE K28: MONTAGUE ISLAND.
FIGURE K35: SOLAR LIGHTING AT
UNSW DESIGNED BY
PHOTOVOLTAIC ENGINEERS.
FIGURE K30: VARIOUS PROJECTS
ARE AVAILABLE AT THE UNSW
FACILITIES AT LITTLE BAY WHERE
THE PHOTOVOLTAIC SYSTEMS ARE
GRID CONNECTED VIA INVERTERS.
FIGURE K29: COMPUTER MODEL-
LING OF PHOTOVOLTAIC DEVICES
GREATLY SIMPLIFIES DESIGN AND
ANALYSIS EXERCISES.
FIGURE K33: THE TRACKING
PHOTOVOLTAIC SYSTEM AT
LITTLE BAY.
FIGURE K34: PROCESSING OF
SOLAR CELLS IN A CLEAN ROOM
ENVIRONMENT.
FIGURE K32: BLUESAT IS A
STUDENT PROJECT TO DEVELOP
& LAUNCH A SMALL SATELLITE
USING UNSW SOLAR CELLS FOR
POWERING THE ELECTRONICS.
PPrroojjeeccttss AAvvaaiillaabbllee oonn CCaammppuussA range of other projects areavailable on campus either inthe device area such as throughtesting, characterization andmodelling, or else with applica-tions such as developing orworking with PV poweredwater pumping systems, orworking with the BLUEsat proj-ect. The latter is a student proj-ect involving students frommany disciplines workingtogether to develop and launcha small satellite with photo-voltaic power for all the elec-tronics and testing.
FIGURE K31: COMMERCIAL SOLAR CELL PRODUCTION LINE
MAKES A GOOD ENVIRONMENT FOR STUDENT PROJECTS.
E D U C A T I O N
K23 �
mine the relative importance of
particular inputs. In this CD-
ROM, every major equation is an
active equation. Examples of
active equations are the calcula-
tion of solar cell fill factors as a
function of both series and
shunt resistance and the calcula-
tion of silicon material parame-
ters based on doping.
EducationalCollaborationOverview
A range of collaborations have been
established between the Key Centre
and other educational institutions
and organizations. Some of these
collaborations are taking place
through the range of projects being
established to give students hands-on
experience in the photovoltaic and
renewable energy areas (see last sec-
tion). In general, collaborations with
other institutions such as Murdoch
University and other organizations
such as the Australian CRC for
R e n e w a b l e
ance. Mr Ted Spooner is an active
member of the international IEC
TC82 Photovoltaics Systems
Working Group for development of
standards. He is also a member of
the Australian EL42 and chairman of
the grid connection subcommittee of
EL42. The University of NSW has a
test facility for grid connected PV
inverters at Little Bay in Sydney and
ACRE is in the process of building
an extensive renewable energy sys-
tems test facility in Perth both of
which are managed by Mr Spooner.
MMuurrddoocchh UUnniivveerrssiittyy
Project Leader:
Professor Stuart Wenham
Recently, Murdoch University
expressed an interest in developing
a new Bachelor of Engineering
similar to the program being imple-
mented at UNSW through the Key
Centre. The Director of the Key
Centre, Professor Stuart Wenham,
is co-ordinating the development of
this new "Renewable Energy
Engineering" program at Murdoch
Energy are important for facilitating
the achievement of the Key Centre’s
aim to act as a national focus for
these activities.
AAuussttrraalliiaann CCRRCC ffoorrRReenneewwaabbllee EEnneerrggyy ((AACCRREE))
Project Leader:
Robert Largent (for year 2000)
A new collaboration was established
between the Key Centre and ACRE
in April 2000 with Robert Largent as
Project Leader. Funding will be pro-
vided by ACRE to support educa-
tional activities conducted by the Key
Centre in the areas of internet cours-
es in renewable energy, high school
education and community education
in the renewable energy area. This
collaboration also includes Curtin
University, the Australian National
University and Murdoch University.
ACRE has also expressed an interest
in providing funding for the develop-
ment of specific courses for use
within the new Bachelor of
Engineering in Photovoltaics and
Solar Energy. An example of such is
the development of a "wind" course
for joint use between the Key Centre
at UNSW and Murdoch University
in Perth.
During the last twelve months, fund-
ing for specific projects was provided
by ACRE in the three areas listed
previously and also in the area of
developing new standards. With
regard to the latter, international
standards are under rapid develop-
ment for stand-alone and grid con-
nected renewable energy systems
through IEC TC82 and IEEE com-
mittees. Australian Standards
Committee EL42 has produced a
standard for stand-alone systems
(AS4509). EL42 plans to progres-
sively develop standards for system
components and system perform-
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K22
Photovoltaics Internet-based short
course as well as the new under-
graduate BE in Photovoltaics and
Solar Energy program. Both of
these courses are run by the Centre
for Photovoltaic Engineering at
The University of New South
Wales, Sydney, Australia.
Each page on the PVCDROM
contains a picture or graphic, an
animation, an active equation, an
interactive graph and/or a simu-
lation. Animations are included
to illustrate and assist in the
understanding of particular con-
cepts. For example, a p-n junc-
tion can be more easily under-
stood if the movement of carri-
ers across the junction is animat-
ed. In the animation for p-n
junctions, each carrier moves in a
random direction for a given
period of time. Carriers that
enter the depletion region are
swept to the other side of the
junction, where they eventually
recombine. An excerpt from an
animation is shown below.
Another useful method of allow-
ing students to develop and test
their understanding is to use
interactive graphs or simulation.
Interactive graphs are useful
where there are a limited number
of input parameters, and the out-
put parameter is a commonly
used graph.
Interactive graphs and simula-
tions are quite similar, except that
a simulation typically has a
greater number of describing
equations and input and output
variables. Because of the com-
plexity of the underlying con-
cepts and mathematical equa-
tions, a simulation provides more
outputs or outputs in a different
form than an interactive graph.
An example of a simulation of
the sun’s position is provided.
"Active" equations can be used
that allow a user to enter inputs
and observe the effects. Active
equations are particularly useful
for concepts that have multiple
inputs but only a single output.
They allow users to get a feel for
the correct numbers and deter-
FIGURE K36: EXCERPT FROM AN
ANIMATION OF A P-N JUNCTION.
FIGURE K37: CALCULATION OF SILICON MATERIAL PARAMETERS
USING ACTIVE EQUATIONS.
FIGURE K39: COLLABORATIVE
EDUCATIONAL ACTIVITIES HAVE
BEEN ESTABLISHED WITH THE
AUSTRALIAN CRC FOR
RENEWABLE ENERGY. CURTIN
UNIVERSITY, THE AUSTRALIAN
NATIONAL UNIVERSITY AND
MURDOCH UNIVERSITY ARE ALSO
PART OF THIS COLLABORATION.
FIGURE K40: THE KEY CENTRE
IS COLLABORATING DIRECTLY
WITH MURDOCH UNIVERSITY
TO ASSIST THE LATTER IN THEIR
DEVELOPMENT OF A NEW BE
IN RENEWABLE ENERGY
ENGINEERING.
FIGURE K38: CALCULATION OF THE PATH OF THE SUN AS A FUNCTION
OF LATITUDE, TIME OF DAY AND TIME OF YEAR.
1KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K24
University with quite a few sub-
jects to be used from the new
Bachelor of Engineering in
Photovoltaics and Solar Energy
at UNSW. Considerable empha-
sis is being placed on the devel-
opment of material able to be
offered via the internet to satisfy
distance learning requirements
for the students at both institu-
tions. Excellent financial support
is also being provided for this
new Renewable Energy Engin-
eering program at Murdoch, par-
ticularly from Western Power,
the Alternative Energy Devel-
opment Board and the Australian
CRC for Renewable Energy. This
new degree will commence in
2001, one year later than the pro-
gram at UNSW. Overall, the
Murdoch University degree will
have less specialist material in
the photovoltaic area but will
give greater exposure to other
renewable energy technologies
of particular importance in WA
such as biomass and wind gener-
ation. Several subjects developed
for the Murdoch degree will also
be made available to students in
the Photovoltaics and Solar
Energy degree. Professor
Wenham’s co-ordinating role has
been formalized through the
offer of an adjunct appointment
at Murdoch for a 3 year period.
TThhaaiillaanndd UUnniivveerrssiittiieess
Project Leader:
Dr Jeff Cotter
Another activity within the Key
Centre for Photovoltaic Engin-
eering is helping overseas universi-
ties who seek collaboration to
enhance undergraduate curriculum
and to improve research expertise
in the renewable energy area. This
activity has immediate benefits to
the foreign institution in addition
to the longer-term benefit of
establishing linkages between these
universities and Australian institu-
tions. Such linkages might lead to
the exchange of undergraduate
students, postgraduate students or
faculty members.
Dr Jeff Cotter recently travelled to
Thailand to visit key personnel at
several universities interested in
photovoltaics: Burapha University
in Bang Saen, Chiang Mai
University in Chiang Mai, and
Ubon Ratchathani University in
Ubon Ratchathani. The main pur-
pose was to discuss issues related
to course curricula, to identify suit-
able teaching resources and to dis-
cuss future research activities in
the renewable energy and photo-
voltaics fields. In addition, Dr
Cotter delivered a one-day work-
shop in Bangkok for a wider audi-
ence that included a brief
overview of renewable energy
resources and technology and
details of recent developments in
photovoltaics technology. In late
March 2000, three Thai faculty
members travelled to Australia
for an 8 week fellowship that
immersed them in both teaching
and research activities at the
Key Centre.
E D U C A T I O N
K25 �
GGeeoorrggiiaa IInnssttiittuuttee ooffTTeecchhnnoollooggyy
Project Leader:
Dr Christiana Honsberg
One of the Key Centre academic
staff, Dr Honsberg, traveled to
the Georgia Institute of
Technology for the purpose of
presenting material relating to
the new educational programs,
resources and techniques being
developed at UNSW in the pho-
tovoltaics area. Both institutions
are interested in further discus-
sions relating to possible oppor-
tunities for collaboration and
faculty exchange.
IInntteerrnnaattiioonnaall EEnneerrggyy AAggeennccyy((IIEEAA))
Staff involved:
Dr Muriel Watt
Mr Ted Spooner
(Electrical Engineering)
UNSW is a member of the
Australian Photovoltaic Power
Systems (PVPS) Consortium for
the International Energy Agency
PVPS program, one of the col-
laborative Research and Dev-
elopment agreements established
within the IEA. UNSW responsi-
bilities are shared between
Solarch and the Photovoltaics
Centre.
The overall program is headed
by an Executive Committee com-
posed of one representative
from each participating country,
while the management of indi-
vidual research projects (Tasks)
is the responsibility of operating
agents.
The Australian consortium is
involved with several program
World SolarChallenge EventProject Leader:
Mr Mark Silver (WWW, Logistics)
Project Leader:
Dr Jeff Cotter (Speed of Light II)
Other Staff:
Dr Christiana Honsberg
Mr Lawrence Soria
Mr Simon Freedman
Professor Stuart Wenham
Professor Martin Green
This year the Centre continued its
tradition of association with the
World Solar Challenge, the world's
premier solar car event racing over
2000km across Australia from
Darwin to Adelaide. The Centre was
tasks, including Task I - Info-
rmation Dissemination; Task III
– Stand-Alone Power Systems;
Task V – PV Grid Connection;
Task VII – PV in Buildings; and
Task IX – PV in Developing
Countries. The consortium
meets four times a year and a
wide range of topical PV infor-
mation is distributed and dis-
cussed. Photovoltaic Centre staff
have been particularly involved
in the activities of Tasks I, V and
VII, with Muriel Watt preparing
the Australian contribution to
the International PV Survey
Report and Ted Spooner
involved with the development
of international grid connection
guidelines.
FIGURE K42: WIND GENERATOR
AT MURDOCH UNIVERSITY
TO BE USED FOR EDUCATIONAL
PURPOSES.
FIGURE K43: LINKAGES HAVE
BEEN ESTABLISHED BETWEEN
THE KEY CENTRE AND
THAILAND UNIVERSITIES.
FIGURE K41: REMOTE AREA
POWER SUPPLY AT MURDOCH
UNIVERSITY.
FIGURE K44: WEB-BASED DISSEMINATION OF INFORMATION
ELATING TO THE 1999 WORLD SOLAR CHALLENGE EVENT.
E D U C A T I O N
K27 �
about the new Bachelor of En-
gineering in Photovoltaics and
Engineering.
TThhee AAuussttrraalliiaa PPrriizzeeSSyymmppoossiiuumm
Project Leaders:
Mr Mark Silver
Professor Stuart Wenham
During last year, the Key Centre
held a symposium for years 11
and 12 high school students.
Featured at the symposium were
Professors Green and Wenham,
the 1999 recipients of the
Australia Prize for Energy
Science and Technology. Other
presentations at the symposium
included: an introduction and
SSuunnsspprriinntt-MMooddeell SSoollaarr CCaarrRRaacciinngg ffoorr HHiigghh SScchhoooollSSttuuddeennttss
Project Leader:
Mr Robert Largent
The Key Centre has taken over
responsibility for organizing the
statewide Sunsprint competition.
Sunsprint is a model solar car rac-
ing competition held annually for
teams of high school students who
design, build and ultimately race
their model cars against other high
school teams. In the most recent
event, 42 entries were received
statewide, involving approximately
300 students. These projects pro-
vide excellent educational oppor-
tunities for the students involved
as they learn more about photo-
voltaics, project design and team-
work. The Key Centre and the
Faculty of Engineering at UNSW
recognize the importance of this
event, not only for its direct educa-
tional benefits, but also as a means
of giving students insight into
engineering in general and specifi-
cally photovoltaic engineering and
solar energy. The winning high
school was Dubbo Christian
School, with the top four placed
cars being sponsored to participate
in the National Titles held in
overview of the new Bachelor
of Engineering in Photovoltaics
and Solar Energy by Dr
Christiana Honsberg; a presen-
tation and demonstration by the
solar car team; and various edu-
cational demonstrations de-
signed to teach students about
engineering, electricity, photo-
voltaics and their potential for
the future. Despite cancellations
due to the teachers’ strike, 180
students from 19 high schools
attended the symposium to
learn more about photovoltaic
devices and applications and
their future potential.
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K26
proud to have been selected by the
race organisers to once again write
the official race report Speed of Light
II: World Solar Challenge and to pro-
vide Internet support by way of a
graphical display of race progress
linked from the race organiser's
home page.
Our special WWW site was designed
by undergraduate thesis student
Simon Freedman and brought on
line to provide global race enthusiasts
and the general public with "on the
fly" consolidated race progress and
information. The site also promoted
the World's First Undergraduate
Degree Program in Photovoltaics
and Solar Energy at UNSW.
Official race data was displayed on an
interactive map of Australia along
with ticker tape headlines, daily race
reports, photo images, videos and
links to the home pages of the official
race organisers and race teams. The
bulk of information for the web site
was provided by Dr Jeff Cotter's in
field "Speed of Light II" team which
took over 2,000 images en route.
At its peak during the World Solar
Challenge, our special race server
downloaded over 210,000 pages in
one day and generated interest in
the Centre ‘s web site which
increased five fold to almost 11,000
requests a day. After the race the site
lives on as a valuable record of race
details and images which will be fur-
ther bolstered by the release of the
book/report Speed of Light II: World
Solar Challenge.
Promotion ofEducationalPrograms
BBrroocchhuurreess
Project Leader:
Ms Lisa Cahill
A range of brochures have been pro-
duced and printed for distribution.
These have been sent to all high
schools in Australia as well as being
used extensively wherever possible to
publicise the educational programs.
Brochures include information
PPHHAASSEE CCDD-RROOMM
Project Leader:
Mr Robert Largent
Educational Officer, Robert Largent,
has co-ordinated and managed a
team of people in the development
of a multimedia CD-ROM for the
primary purpose of promoting the
new Bachelor of Engineering in
Photovoltaics and Solar Energy. This
CD-ROM gives an overview of pho-
tovoltaics and the range of renew-
able energy technologies. It also pro-
vides background material on the
growth in the related industries and
the corresponding job creation that
has necessitated the establishment of
this program. A detailed outline of
the course has been provided as well
as descriptions of the individual sub-
jects and their content. An introduc-
tion to the staff of the Key Centre
and their background areas of
expertise are provided. There is also
an overview of the achievements of
the Photovoltaic Centre during the
last 15 years of world leadership in
device research and technology
development. Approximately 12,000
FIGURE K46: CD-ROMS DEVELOPED TO PROMOTE THE NEW
DEGREE IN PHOTOVOLTAICS AND SOLAR ENERGY.
FIGURE K47: ELECTRICITY DEMON-
STRATION FOR STUDENTS.
FIGURE K49: THE SUNSPRINT
STATE-WIDE COMPETITION FOR
MODEL SOLAR CAR RACING IS
HELD AT UNSW.
FIGURE K48: EACH MODEL
SOLAR CAR IS DESIGNED AND
DEVELOPED BY A TEAM OF HIGH
SCHOOL STUDENTS.
FIGURE K50: SOLAR CAR DESIGNED, DEVELOPED,
BUILT AND RACED BY UNSW STUDENTS.
FIGURE K45: SOLAR CARS
COMPETING IN THE
WORLD SOLAR CHALLENGE.
sheets on a range of topics, leaflets to
advertise particular Centre activities
and brochures aimed specifically to
disseminate information about the
new degree program.
copies of the CD-ROM have been
produced and made available free of
charge to careers’ advisors in all high
schools throughout Australia and to
anyone else interested in learning
1E D U C A T I O N
K29 �
The VWSC has been developed
under the leadership of Dr Jeff
Cotter as an educational tool with-
in the new degree program and
also for promotional purposes.
Solar-powered racing cars are par-
ticularly suited for educating peo-
ple of all levels about the engineer-
ing of photovoltaic systems. They
have broad appeal because they are
quite fascinating and dynamic, and
since there are always winners and
losers, there is an element of
drama, strategy and tactics that is
not found in most PV systems.
Solar-powered racing cars also rep-
resent a truly multi-disciplinary
engineering problem, which makes
them an ideal learning opportunity
for university and high-school stu-
dents. In fact, more than three-
quarters of the entrants in the lat-
est World Solar Challenge race from
Darwin to Adelaide were either a
university or a high-school team.
Solar racing cars bring together the
principles of several engineering
fields like no other project: automo-
tive engineering (suspension and
siderable simplification of the techni-
cal issues of racing car design, which
was accomplished with a "Design
Workshop", where players select
from a list of options for the body of
the car, the solar array, the battery and
other car features. Integral to the
workshop is a set of tutorial pages
that provide a brief overview on each
of the main technical issues of racing
cars. Each entrant must then design
their own car within the overall budg-
etary constraints imposed.
Once the design phase is complete
(it usually takes five to ten minutes
to complete), the player races in the
"Virtual World Solar Challenge", a
simulated race from Darwin to
Adelaide. The racing console pro-
vides important telemetry, weather
and strategy information in a graph-
ical format. The main display indi-
cates the present speed, battery-
state-of-charge, solar intensity,
motor power and weather forecast,
all displayed on a virtual car dash-
board, along with a front screen
view out of the car. Three small
graphs on the main console display
the battery-state-of-charge, speed
and solar intensity for the last 9 hours
of racing. The complete telemetry
history is available on a separate page.
To give the game the flavour of a
race, several computer-generated
players compete in each race, and
steering), aerospace engineering
(aerodynamics), chemistry (batter-
ies), mechanical engineering (chas-
sis design), photovoltaics (solar cells
and arrays), and electrical engineer-
ing (telemetry, electronics, motors
and communication). These cars
are also one of the most highly
optimised PV systems, and there-
fore there is significant depth in
addition to breadth in these engi-
neering problems.
Furthermore, solar racing cars have
several interesting design constraints
and conditions that are not usually
associated with PV systems. For
example, array area and battery
capacity are restricted by race regula-
tions, and system cost is not always
an important factor. Also, the weath-
er conditions and forecast, including
cloud cover, wind and temperature,
take on a whole different meaning
for racing cars.
During the last year, the Key Centre
set out to capture the essence of
designing and racing a solar car in a
fast, visually pleasing, browser-based
game at a level suitable for secondary
school children. This requires con-
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K28
Adelaide in conjunction with the
World Solar Challenge.
The two major sponsors of the
Sunsprint competition were the
Key Centre for Photovoltaic
Engineering and the Faculty of
Engineering at UNSW. Generous
sponsorship was also provided
by the Australian CRC for
Renewable Energy, BP Solarex,
Farnow Pty Ltd, and General
Technology Pty Ltd.
This year, the Key Centre
intends to make even greater use
of this event as a means for edu-
cating high school students
about photovoltaics, renewable
energy technologies and the new
Bachelor of Engineering in
Photovoltaics and Solar Energy.
In conjunction with this, greater
emphasis will be placed on using
web-based dissemination of
information, both prior to and
during the Sunsprint competition
to provide high schools around
the State and country with race
information and educational
material.
SSppoonnssoorrsshhiipp ooff SSoollaarr CCaarr PPrroojjeecctt
Project Leaders:
Dr Jeff Cotter
Associate Professor Paul Basore
The Centre has provided signifi-
cant levels of sponsorship for the
UNSW solar car, for two purposes.
The first purpose is to create addi-
tional opportunities for students
from the Centre to engage in solar
energy related projects. Dr Jeff
Cotter is actively involved in this
area in terms of team management
and technology development. The
second purpose is to promote the
new Bachelor of Engineering in
Photovoltaics and Solar Energy
program. Racing team members
fulfill their sponsorship obligations
by distributing brochures and CD-
ROMs on behalf of the Key
Centre at Solar Car Races and
other activities. Team members
also provide demonstrations and
presentations at Key Centre pro-
motional activities such as the
Australia Prize Symposium. In addi-
tion, they have participated and
assisted in the production of a pro-
motional video for the new BE in
Photovoltaics and Solar Energy.
VViirrttuuaall WWoorrlldd SSoollaarrCChhaalllleennggee ((VVWWSSCC))
Project Leader:
Dr Jeff Cotter
Other Staff:
Mr Mark Silver
Mr Simon Freedman
FIGURE K51: CONSOLE
FOR THE VIRTUAL WORLD
SOLAR CHALLENGE. THIS CAN
BE FOUND ON THE CENTRE FOR
PHOTOVOLTAIC ENGINEERING
WEBSITE.
FIGURE K52: BATTERIES ARE
IMPORTANT FOR SOLAR CARS.
FIGURE K53: SOLAR CAR
PRODUCED BY LAKE
TUGGERANONG HIGH SCHOOL
FROM WHERE SEVERAL NEW
STUDENTS HAVE ENTERED THE
NEW UNSW DEGREE.
FIGURE K54: MANY PARTS
GO TOGETHER TO MAKE UP
A SOLAR CAR.
FIGURE K55: DESIGNING CARS
FOR THE VWSC.
FIGURE K56: EDDIE FU, WINNER OF THE MOST RECENT VWSC NATIONAL
COMPETITION FOR HIGH SCHOOL STUDENTS RECEIVES HIS CASH PRIZE
AND PLAQUE FROM PROFESSOR WENHAM. KINGSGROVE HIGH SCHOOL
PRINCIPAL, MR BOB IRELAND, RECEIVES THE CORRESPONDING PLAQUE
ON BEHALF OF HIS SCHOOL.
FIGURE K57: DR JEFF COTTER
GIVING DEMONSTRATIONS
TO STUDENTS INVOLVING
ELECTRICITY.
E D U C A T I O N
K31 �
mation kits, brochures and CD-
ROMs were also made available at
this location. Thirdly, the
Sunsprint model solar car racing
took place in the Quadrangle,
under the leadership of Robert
Largent. Based on the numbers of
on-lookers, this appeared to be
the most well attended activity on
campus. Large numbers of stu-
dents from high schools through-
out Sydney and NSW attended
throughout the day as their
respective teams competed in the
Sunsprint competition. Centre
staff, where possible, mixed with
the students providing informa-
tion and advice about the new
degree in Photovoltaics and Solar
Energy. Fourthly, short lectures
were provided by Professor
Wenham in the Matthews
Theatre, specifically for the pur-
pose of providing information
and advice relating to the new
engineering degree. These lec-
tures were particularly well
attended thanks to advertising
that took place at the other three
venues listed above.
SSttuuddeenntt VViissiittss
Project Leader: Mr Robert Largent
Various student visits have taken
place as groups from specific schools
have toured the photovoltaic labora-
tories. Similarly, Centre staff have
made themselves available at various
times throughout the year to give pre-
sentations at specific schools and
high-profile events such as Sci Fest.
At Sci Fest the Centre for
Photovoltaic Engineering in conjunc-
tion with the UNSW Outreach
Centre for Sciences entertained and
educated over 3,500 students in the
fields of energy, high-voltage electric-
ity and magnetism.
PPrroommoottiioonnaall VViiddeeoo
Project Leaders:
Mr Robert Largent
Professor Stuart Wenham
The Key Centre has jointly
funded, with the Faculty of
Engineering, a promotional
video based on solar car racing
activities. The original scope of
the video has been broadened to
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K30
the current standings are dis-
played on a small leader board.
Of course, as in just about any
computer-based game, there is a
"World Records" screen contain-
ing the all-time top 1,000 entries.
A high school competition is
conducted anually with a cash
prize and plaque for the most
recent winner, Eddie Fu from
Kingsgrove High School. Since
the game went on-line, it’s been
played over 7000 times by people
from all over the world.
The game can presently be found
on the World Wide Web at
www.pv.unsw.edu.au. It is open
to players of any age or affilia-
tion and can be played as many
times as desired.
IInnffoorrmmaattiioonn DDaayyss
Project Leader:
Ms Lisa Cahill
Several information days have been
held during the last year. The faculty
of Engineering has widely advertised
these events to high school students.
The events have varied in nature, but
in general include activities such as
short lectures, attendance at informa-
tion desks, tours of the photovoltaic
laboratories, various demonstrations
involving photovoltaic technology
and systems, exposure to the VWSC
and the provision of information kits
for all enquirers. These information
days have, in general, involved Key
Centre staff and have also benefited
greatly through contributions from
various PhD students.
UUnniivveerrssiittyy OOppeenn DDaayy
Project Leaders:
Mr Mark Silver (Demonstrations
& Tours)
Mr Robert Largent (Sunsprint Competition)
Ms Lisa Cahill (Information Desks)
Professor Stuart Wenham (Public Lectures)
The University Open Day was a
major event for the Centre for
Photovoltaic Engineering staff
and postgraduate students. Pro-
motional activities took place at
four different locations through-
out the day. Firstly, two staff
members attended information
desks in the Roundhouse to pro-
vide advice, information, and
information kits to all enquirers
about the new BE in Photo-
voltaics and Solar Energy.
Secondly, outside the Science
Theatre, a couple of demonstra-
tions were displayed and operated
throughout the day, including
the solar car and solar powered
orange juicing machines. Infor-
FIGURE K58: PV DISPLAYS AT
UNIVERSITY OPEN DAY.
FIGURE K59: PROFESSOR
WENHAM DISCUSSES THE NEW
BE IN PHOTOVOLTAICS AND
SOLAR ENERGY WITH STUDENTS
FROM KINGSGROVE HIGH
SCHOOL.
FIGURE K60: TWO STUDENTS LEARNING ABOUT ELECTRICITY.
FIGURE K61: THE 1999 AUSTRALIA PRIZE SYMPOSIUM TOOK PLACE
TO RAISE HIGH SCHOOL AWARENESS OF PHOTOVOLTAICS AND
THE NEW DEGREE IN PHOTOVOLTAICS AND SOLAR ENERGY.
include the use of all UNSW
technologies used in the solar
car racing events, particularly the
solar cell technologies that have
been preferred by the leading
cars in most races over the last
decade. The video will also
include material specifically
relating to the new degree in
Photovoltaics and Solar Energy
and will even include interviews
with students enrolling in the
new program.
PPuubblliisshheedd MMaatteerriiaall
Various opportunities have existed
for publishing educational material
about the new undergraduate engi-
neering program. Papers have been
either published at or accepted for
publication at the 11th International
Photovoltaic Science and Engi-
neering Conference (Japan), ANZS-
ES Conference (New Zealand),
the 16th European Photovoltaic
Solar Energy Conference (Scotland),
and the ISREE 2000 Seventh Inter-
national Symposium on Renewable
Energy Education (Norway).
In addition, a paper specifically
focusing on the innovative
aspects of the new program has
been accepted for publication in
a special issue of Solar Energy
Materials and Solar Cells while a
manuscript detailing the new
degree program was published
in the special educational issue
of the ISES trade journal, Solar
Progress. Other publications
include many published articles
in the printed media as well as
interviews for radio and televi-
sion. The latter articles and
interviews have been conducted
for their newsworthy value and
hence have not incurred costs
for the Key Centre.
1
Industry Funded Collaborative ResearchIndustry Funded Collaborative Research
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K32
The Key Centre has successfully
achieved its aim of establishing
collaborative research programs
with all Australian manufacturers
of photovoltaic devices. The
final program to be established
was a collaboration with Solarex
to develop a new technology to
satisfy the requirements of their
multi-crystalline silicon sub-
strates All the collaborative
research projects conducted
under the umbrella of the Key
Centre are self funding with no
ARC Key Centre funds being
used to support the work. This is
consistent with the guarantee
provided by the applicants in the
original Key Centre proposal
stating that all industry collabo-
rative research projects would be
conducted on a "full incremental
cost recovery basis". Due to the
importance and success of some
of these collaborative research
projects, academics from the Key
ect to have been established under
the joint collaborative research agree-
ment between Europe and Australia.
Despite this however, no funding has
yet been forthcoming from the
Australian Government to support
the project. In comparison, signifi-
cant levels of funding (well in excess
of $100,000 per year) is being con-
tributed through the European
Commission JOULE III Program
(contract JOR3-CT98-0294) to sup-
port our European partners from
England and Spain. To allow addi-
tional areas of academic interest to
be explored in this work, funding has
also been contributed from the ARC
Special Investigator’s Award, in the
name of Professor Wenham.
Virtually all commercially pro-
duced silicon solar cells suffer
from high rear surface recombina-
tion velocities. This does not in
general seriously degrade device
performance, as in general the sub-
strate thicknesses are greater than
the minority carrier diffusion
lengths. Future generations of
commercial technology, however,
need to be able to utilise substan-
tially thinner substrates to improve
the economics and also potentially
give performance enhancement.
At present, the use of thinner sub-
strates with existing commercial
cell technology will simply lead to
performance degradation.
This collaborative research pro-
gram has been established with
BP Solar to develop a rear contact-
ing scheme that simultaneously
achieves a much lower rear surface
recombination velocity. Direct
comparison between devices fabri-
cated using these new designs and
devices using more conventional
contacting schemes typical of
those used commercially, has led to
the demonstration of approxi-
Centre have been able to success-
fully apply for other funding to
support the work such as through
the SPIRT Grant Scheme and the
European Commission JOULE
program.
Project with BP Solar (now BP Solarex)
Project Leader:
Professor Stuart Wenham
Other Staff:
Dr Tim Bruton (BP Solar)
Mr Nigel Mason (BP Solar)
PhD Students:
Ms Linda Koschier
Mr Stephen Pritchard
This project has been initiated by
BP Solar, who is directly funding
the corresponding work at UNSW.
It appears that this is the only proj-
I N D U S T R Y C O L L A B O R A T I O N
K33 �
mately 40mV improvement in
open circuit voltage and a corre-
sponding performance enhance-
ment of 5-10%. Importantly, this
performance enhancement will
increase significantly as thinner
substrates are used.
The work in this project at
UNSW should come to comple-
tion during the next year with the
expected performance gains hav-
ing been achieved. The next
stages of this work will involve
transferring these developments
to BP Solar and eventually to
large scale production. As a pre-
liminary step towards these latter
goals, a PhD student, Linda
Koschier, working on this project,
traveled to BP (UK) for approxi-
mately one month to investigate
the feasibility of fabricating similar
devices using the BP Solar facili-
ties. This trip was also fully funded
by BP Solar.
Project withEurosolare
Project Leader:
Dr Christiana Honsberg
Other Staff:
Dr Jeff Cotter
Dr Francesca Ferrazza
(EuroSolare, Italy)
PhD Student:
Mr Bryce Richards
This project is being funded directly
by Eurosolare from Italy who
requested this collaborative project
following their licensing of the
buried contact technology. Addi-
tional funding was successfully
gained through the ARC SPIRT
the successful completion of the
technology optimisation program.
The first stage of the correspon-
ding technology transfer took
place recently in the laboratories at
UNSW during which Eurosolare
technicians, researchers and pro-
duction staff were trained in the
new technology.
Project with PacificSolar Pty Ltd
Project Leaders:
Professor Stuart Wenham
Professor Martin Green
Other Staff:
Mr Robert Bardos
Dr Tom Puzzer
Non-UNSW Staff:
Dr Z. Shi (Pacific Solar, Sydney)
Dr A. B. Sproul (Pacific Solar, Sydney)
PhD Students:
Mr Oliver Nast
Mr Nick Shaw
Pacific Solar Pty Ltd was estab-
lished as a joint venture between
Pacific Power and UNSW for the
purpose of commercializing the
new generation of thin film tech-
nology developed at UNSW. Due
grant scheme in the name of Dr.
Honsberg. This additional funding
has facilitated a broadening of the
scope of the project to include
work not considered to be of
immediate commercial application
but nevertheless closely related to
the basic concepts. No Key Centre
funding has been used to support
this project.
Despite the commercial success of
the buried contact solar cell, a sig-
nificant deterrent to the technolo-
gy’s uptake has been the necessity
for industry to invest in entirely
different infrastructure and equip-
ment for it’s manufacture, com-
pared to existing screen printed
cell technology. The aim of this
collaborative research program
with Eurosolare is to adapt the
buried contact solar cell for fabri-
cation using existing screen print-
ing equipment and infrastructure.
TTeecchhnnoollooggyy TTrraannssffeerr
A highlight of this collaboration
and an indication of its success has
been Eurosolare's decision to
license the UNSW technology.
This decision has been made prior
to the completion of the project,
indicating the confidence held for
Introduction
The Key Centre’s research involvement is very much
motivated by its importance to the educational programs. It
therefore focuses on industry collaborative research involv-
ing technologies of commercial and educational importance.
FIGURE K62: THE KEY CENTRE HAS A COLLABORATIVE RESEARCH
PROJECT WITH BP SOLAR, THE WORLD’S LARGEST PHOTOVOLTAIC
MANUFACTURER AND LICENSEE OF UNSW TECHNOLOGY.
FIGURE K63: EUROSOLARE KEY PERSONNEL IN ATTENDANCE AT
UNSW DURING TECHNOLOGY TRANSFER AND MEETINGS IN
RELATION TO THE COLLABORATIVE RESEARCH.
I N D U S T R Y C O L L A B O R A T I O N
K35 �
excessive degradation in minori-
ty carrier lifetimes. This con-
straint in general makes it diffi-
cult to produce heavily diffused
regions beneath metal contacts.
In this new collaborative
research program negotiated
with Solarex, new approaches
for selective diffusion are being
developed and used to provide
heavily doped regions at the
semiconductor surface where
the metal contacts are to be
located. Self-alignment for the
metallization is a further aim, to
be achieved by ensuring that the
integrity of an overlying dielec-
tric layer is destroyed during or
prior to the selective doping as
is the case with the convention-
al buried contact solar cell.
Producing the metal contact in
this way may alleviate the need
for high temperature exposure
of the multi-crystalline sub-
strates. Nevertheless, the new
technology appears capable of
still achieving very fine line
widths and hence many of the
corresponding high perform-
ance attributes normally associ-
ated with the buried contact
solar cell. Furthermore, the
heavy doping beneath the metal
provides excellent ohmic con-
tact as well as minimising the
contribution to the dark satura-
tion current from the metal/sili-
con interface.
Funding for this work, will be
provided by Solarex, with addi-
tional funding being sought
through alternative schemes,
such as the SPIRT Grant
Scheme. As is consistent with
the Key Centre policy, no ARC
Key Centre funding will be used
to support this project. Work is
expected to commence during
the next twelve months but may
be delayed due to the merger
between the major oil compa-
nies BP and Amoco.
Inverter Design
Project Leaders:
Professor Martin Green
Dr Sean Edmiston (Pacific Solar,
Sydney)
Other Staff:
Professor Stuart Wenham
Mr Ted Spooner (Electrical
Engineering)
Mr David Roche
PhD Student:
Mr Bradley O’Mara
The new Pacific Solar product is
expected to be a photovoltaic
module with integral inverter
for grid connection. A major
research program has been
established by Pacific Solar to
develop appropriate low-cost,
high-efficiency, high-reliability
inverters. The collaborative pro-
gram was established with
UNSW well before commence-
ment of the Key Centre,
with the aim being to make
available the vast experience,
facilities and equipment of
UNSW and its researchers to
assist with the development
of this new inverter. As work on
this project nears completion,
the collaboration has taken on
more the form of a consultancy
with work only taking place
when requested by Pacific Solar
who funds the work.
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
� K34
to commercial sensitivities, the
commercial implementation of
the technology takes place
exclusively at the premises of
Pacific Solar, with no involve-
ment from UNSW. However,
this collaborative research pro-
gram has been established,
whereby the expertise and facili-
ties of UNSW are able to be
used to assist in characterizing
and analyzing materials and
device structures to comple-
ment the commercialization
program at Pacific Solar. The
success of this collaborative
project is partly attested to by a
recent press release from Pacific
Solar announcing the successful
implementation of pilot pro-
duction of the new technology
six months ahead of schedule.
Pilot production modules are
approximately 30cm x 40cm as
shown in Figure K65. The com-
pany anticipates scaling up
the technology to full-
scale production in
the near future.
Substantial lev-
els of fund-
ing have
been provid-
ed by Pacific
Solar to support
this collaborative
project. Additional
funding has been suc-
cessfully sought through
the ARC SPIRT Scheme
in the names of Wenham,
Sproul and Shi. To allow further
broadening of the scope of this
work to include the study of
metal induced crystallization for
forming continuous polycrys-
talline silicon layers of high
quality directly onto glass, fund-
ing has also been made available
from the ARC Special
Investigator’s Award in the
name of Professor Wenham. No
Key Centre funding has been
used to support this work.
Project withSolarex (now BP Solarex)
Project Leader:
Professor Stuart Wenham
Other Staff:
Dr Christiana Honsberg
Dr Jeff Cotter
Multicrystalline silicon substrates
in general cannot withstand the
same high temperature exposure
as single crystal silicon substrates.
Prolonged high
t e m p e r a t u r e
e x p o s u r e
c a u s e s
FIGURE
K65:
THIN FILM
PHOTOVOLTAIC
MODULE FABRICATED
ON THE PACIFIC SOLAR
PILOT PRODUCTION LINE
USING UNSW DEVELOPED
TECHNOLOGY.
FIGURE K64: DR SHI IN THE LABORATORIES AT PACIFIC SOLAR,
WHERE COLLABORATIVE RESEARCH WORK IS CONDUCTED BETWEEN
UNSW AND PACIFIC SOLAR.
P U B L I C A T I O N S
K37 �
Nast, O., Brehme, S., Neuhaus, D.-H. and
Wenham, S.R., Polycrystalline Silicon Thin
Films on Glass by Aluminium-Induced
Crystallisation, IEEE Trans. on Electron
Devices, Vol. 46, p. 2062, 1999.
Nast, O., Brehme, S., Pritchard, S., Aberle,
A. G., and Wenham, S. R., Aluminium-
Induced Crystallisation of Silicon on Glass for
Thin-Film Solar Cells, Solar Energy Materials
and Solar Cells.
Patents and Patent
ApplicationsGreen, M. A., Wenham, S. R., Ji, J. J.,
Basore, P. A., Shi, Z., Thin Films With Light
Trapping, International Patent No.
PCT/AU99/00979, 1999.
Wenham, S. R., Green, M. A., Honsberg, C.
B. Metallisation for Buried Contact Solar Cells,
Australian Patent, April 1999.
Research Reports and
Non-Refereed PublicationsA. B. Sproul, T. Puzzer and R. Bardos, TDG
Device Characterisation Progress Report, Pacific
Solar Final Reports, Volume 5, February,
1999, pp41-43.
Aberle, A. G. and Wenham, S. R., Overview
on the high-efficiency solar cell research activities at
the University of New South Wales, Symposium
Proceedings, Research Collaboration Sym-
posium, 1st Australian Technology Week in
Taiwan, Taipei, Taiwan, April 1999.
Bardos, R., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, May, 1999, pp199-202.
Bardos, R., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, June, 1999, pp219-220.
Bardos, R., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, September, 1999, pp349.
Bardos, R., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, November, 1999, pp439-440.
Bruton, T. M., Mason, N. B., Ruiz, J. M. and
Wenham, S. R., Next Generation 20% efficient sil-
icon solar cells – NEXTGEN First Periodic
Report (1/7/98 to 31/12/98), The European
Commission JOULE III, Contract JOR3-
CT98-0294, March, 1999, 9 pages.
Bruton, T. M., Mason, N. B., Ruiz, J. M. and
Wenham, S. R., Next Generation 20% efficient
silicon solar cells – NextGen Second Periodic
Sproul, A. B., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, June, 1999, pp217-218.
Sproul, A. B., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, July, 1999, pp259-262.
Sproul, A. B., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, August, 1999, pp301-304.
Sproul, A. B., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, September, 1999, pp343-348.
Sproul, A. B., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, November, 1999, pp433-438.
Sproul, A. B., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, December, 1999, pp471-476.
Wenham, S. R., Eurosolare Technology Transfer
Report, April 1999, 114 pages.
Wenham, S. R., Technical Progress Report –
NEXTGEN, presented to BP Solarex, 23rd
March, 1999, 16 pages.
Wenham, S. R., Koschier, L. M. and Green,
M. A., NEXTGEN Annual Report, submitted
to BP Solarex, 12th August, 1999, 4 pages.
Wenham, S. R., Technical Progress Report –
NEXTGEN, presented to BP Solarex, 10th
February, 1999, 2 pages.
Report (1/1/99 to 30/6/99), The European
Commission JOULE III, Contract JOR3-
CT98-0294, September, 1999, 18 pages.
Cotter, J., Honsberg, C., Wenham, S. R. and
Leo, T., Proposed Collaborative Agreement
between UNSW and Solarex, February, 1999,
10 pages.
Green, M. A. and Wenham, S. R., Technical
Progress Report – NEXTGEN, presented to
BP Solarex, 10th June, 1999, 12 pages.
Honsberg, C., Cotter, J., Silver, M. and
Wenham, S., Technical Report on Progress:
UNSW/Eurosolare collaboration, August
1999, 5 pages.
Koschier, L. M., Progress Report on
NEXTGEN Activity, BP Solarex, Sunbury,
December, 1999.
Puzzer, T. and Bardos, R., TDG Device
Characterisation Progress Report, Pacific Solar
Final Reports, Volume 5, December, 1999,
pp477-478.
Puzzer, T., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, April, 1999, pp151-162.
Puzzer, T., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, May, 1999, pp209-210.
R. Bardos, TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, April, 1999, pp149-150.
Richards, B., Proposed work for
UNSW/Eurosolare collaboration, Presented to
Eurosolare, March 1999, 11 pages.
Sinton R., and Sproul, A. B., Material
Characterisation Progress Report, Pacific Solar
Final Reports, Volume 5, January, 1999,
pp15-20.
Sproul, A. B., STDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, April, 1999, pp145-148.
Sproul, A. B., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, March, 1999, pp97-100.
Sproul, A. B., Puzzer, T. and Bardos, R.,
TDG Device Characterisation Progress Report,
Pacific Solar Final Reports, Volume 5,
October, 1999, pp395-400.
Sproul, A. B., TDG Device Characterisation
Progress Report, Pacific Solar Final Reports,
Volume 5, May, 1999, pp203-208.
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
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EducationBooks and CD-ROMsAberle, A. G., Crystalline Silicon Solar Cells —
Advanced Surface Passivation and Analysis,
Sydney, Centre for Photovoltaic
Engineering, University of New South
Wales, ISBN 0 7334 0645 9, September,
1999, 340 pages.
C.B. Honsberg and S. G. Bowden, Photovoltaics:
Devices, Systems and Applications, Vol. 1, ISBN 0-
7334-0596-7, September, 1999.
M. A. Green, Power to the People, UNSW
Press, (in press).
Journal and Conference
PublicationsCotter, J.E. and Freedman, S., Speed of Light –
Virtual Solar Car Racing, Solar Progress, Vol.
20, No. 4, December 1999, p. 29.
Green, M.A. and Wenham, S.R., Photovoltaics
for the New Millennium, Conf. Record,
Australian Institute of Energy National
Conference, Melbourne, November, 1999,
pp44-52.
Honsberg, C. B., Multimedia Educational
Software in Photovoltaics, Solar Progress, Vol.
20, No. 4, December 1999, pp10-11.
Outhred, H. and Watt, M., Prospects for
Renewable Energy in the Restructured Australian
Electricity Industry, World Renewable Energy
Congress, Perth, W.A., 10-13 February 1999.
Watt, M. and Outhred, H., Australian and
International Renewable Energy Policy Initiatives,
World Renewable Energy Congress, Perth,
W.A., 10-13 February, 1999.
Watt, M. and Outhred, H., Implementing the
Renewable Energy Target, Outlook 99,
ABARE Conference, Canberra, A.C.T., 17-
18 March, 1999.
Watt, M. and Outhred, H., Review of Policy
Options for the Australian Renewable Energy
Industry, Solar 99, 37th ANZSES
Conference, Geelong, Vic, 1-3 Dec, 1999.
Wenham, S. R., Honsberg, C. B., Watt, M,
Green, M. A., Cotter, J., Largent, R., Silver,
M. D., Aberle, A. G., Spooner, T., and Cahill,
L., World’s First Bachelor of Engineering in
Photovoltaics and Solar Energy, 7th International
Symposium on Renewable Energy
Education, Oslo, (in press).
Wenham, S. R., Outhred, H., Jennings, P.,
Lee, P., New Undergraduate Engineering
Programs in Renewable Energy, 7th
International Symposium on Renewable
Energy Education, Oslo, (in press).
Wenham, S. R., Potential Role of Solar Energy
in the Next 20-50 Years, Energy for the
Future Conference, Australian Academy of
Technological Sciences and Engineering,
November 1999, 14 pages.
Wenham S.R., Aberle A.G., Photovoltaic tech-
nology at the University of New South Wales,
Workshop Proceedings, Workshop on
Renewable Energy, Perth, Australia, Feb.
1999, pp34-39.
Wenham, S. R., Education for Photovoltaics and
Solar Energy, Solar Progress, Vol. 20, No. 4,
December 1999, pp4-5.
Wenham S.R., Honsberg, C.B., Cotter, J.,
Largent, R., Aberle, A., Spooner, T. and
Green, M.A., Opportunities Arising Through
Rapid Growth of the Photovoltaic Industry, Tech.
Digest, 11th International Photovoltaic
Science and Engineering Conference,
Sapporo City, September, 1999, pp525-526.
Wenham, S.R., Honsberg, C.B., Cotter, J.,
Largent, R., Aberle, A.G., Spooner, T. and
Green, M.A., Australian Educational and
Research Opportunities Arising through Rapid
Growth of the Photovoltaic Industry, Solar
Energy Materials and Solar Cells, (in press).
Education Reports and
Non-Refereed PublicationsCotter, J.E., STA Final Report - Energy
Engineering Sub-Group – Renewable and
Photovoltaics Energy Conversion Technology,
Thailand-Australia Science and Engineering Project
Final Report, 1999, (19 pp.)
Honsberg, C., Progress in UNSW Photovoltaic
Educational Activities, prepared for presentation to
Georgia Institute of Technology, November
1999, 20 pages.
Largent, R., Contribution for Information and
Community Education Quarterly Report #1,
ACRE Project 7.4, April 1999.
Largent, R., Contribution for Information and
Community Education Quarterly Report #2,
ACRE Project 7.4, July 1999.
Largent, R., Contribution for Information and
Community Education Quarterly Report #3,
ACRE Project 7.4, October 1999.
Largent, R., Contribution for Information and
Community Education Quarterly Report #4,
ACRE Project 7.4, December 1999.
Wenham, S. R., Collaborative Agreement Report
for Renewable Energy Engineering Program, sub-
mitted to Dean of Engineering, Murdoch
University, July 1999, 8 pages.
Wenham, S. R., Proposed Renewable Energy
Engineering Program for Murdoch University,
submitted to Dean of Engineering,
Murdoch University, August 1999, 4 pages.
Wenham, S. R., Progress Report on New Degree
Development, submitted to Key Centre
Management Committee, UNSW and Dean
of Engineering, Murdoch University,
November 1999, 9 pages.
ResearchDue to commercial sensitivities associated
with industry funded collaborative research
programs, most of the published material
has been in the form of company reports
that are "commercial-in-confidence". Some
material however, usually associated with
the activities of PhD students working on
the respective projects, has been able to be
published in refereed journals.
Consequently, as listed below, all but one of
these publications have a PhD student as
the first listed author.
Refereed JournalsHonsberg, C.B., Cotter, J.E., Richards B.S.,
Pritchard, S.C., Wenham, S.R., Design
Strategies for Commercial Solar Cells Using the
Buried Contact Technology, IEEE Transaction
on Electron Devices, Vol 46 no. 10,
pp1984-1992, (1999).
Koschier, L.M., Wenham, S.R. and Green,
M.A., Modeling and Optimization of Thin-Film
Devices with Si1-xGex Alloys, IEEE Trans. on
Electron Devices, Vol. 46, pp2111-2115,
October, 1999.
Koschier, L.M., Wenham, S.R., Improved Voc
using Metal Mediated Epitaxial Growth in
Thyristor Structure Solar Cells, Progress in
Photovoltaics, (in press).
Nast, O. and Hartmann, A. J., Influence of
Interface and AI Structure on Layer Exchange
during Aluminium-Induced Crystallisation of
Amorphous Silicon", Journal of Applied
Physics (in press).
Nast, O. and Wenham, S. R., Elucidation of
the Layer Exchange Mechanism in the Formation
of Polycrystalline Silicon by Aluminium-Induced
Crystallisation, Journal of Applied Physics
(in press).
PublicationsPublications
0sF I N A N C I A L S
K39 �
institution, the University of
New South Wales. These funds
comprise 27.5% of the total
income and encompass support
for a range of Key Centre activ-
ities including the Centre
Director’s salary and the pro-
cessing laboratory upgrade to
satisfy new safety regulations.
A breakdown of the expenditure
of funding from the ARC Key
Centre’s Scheme is also provided.
Even though this source of
During 1999, an extensive budg-
etary reconciliation process was
necessary for the establishment
of the Key Centre as an inde-
pendent financial unit from the
School of Electrical Engin-
eering. The financial details
associated with this budgetary
reconciliation are provided in
the annual report for the Centre
for Photovoltaic Engineering.
income comprised only 15.7% of
the Key Centre’s total income,
few of the Key Centre’s activities
would have been feasible without
this important component. Of
this funding, 50% was spent on
salaries while 20% was spent on
equipment and 20% on consum-
ables for Key Centre operations.
The final 7.8% was spent on trav-
el, particularly in relation to the
establishment of collaborative
teaching programs with other
institutions and organisations.
KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG
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The Key Centre for Photo-
voltaic Engineering was estab-
lished in January 1999 under the
Australian Research Council’s
Key Centres Scheme. The docu-
mentation and budget in the
original proposal for the Key
Centre indicated that no ARC
Key Centre funds would be used
to support the research projects
for the Key Centre. Instead, the
industry collaborative research
projects must all be self-funding
through industry and other
sources such as ARC SPIRT
grants. The total income for the
Key Centre in the year 1999 was
approximately $2m of which the
ARC Key Centre funds com-
prised 15.7%. This indicates the
success of the Key Centre in
attracting other sources of
income such as from industry
and teaching activities, therefore
maximising the impact of the
ARC funding.
The breakdown of Key Centre
income for 1999 according to
source is provided, with 17%
being earned from EFTSUs
through teaching activities. Also
from the University Operating
Grant is a research quantum
component of a further 13.3%.
Collaborative programs in
research and teaching facilitated
additional income from other
organisations such as the
Australian CRC for Renewable
Energy, Pacific Solar Pty Ltd,
BP Solar, Eurosolare and the
Sustainable Energy Devel-
opment Authority. Several other
industry sponsors have gener-
ously contributed to the
Sunsprint model solar car race
run by the Key Centre, con-
tributing a further 1.9% of the
Key Centre’s total income. With
regard to collaborative research
funding, one of the largest
sources has been the ARC
SPIRT Scheme, indicating the
quality and innovativeness of
the work being conducted. The
SPIRT Grants have contributed
a similar amount towards the
research of the Key Centre as
the Key Centre’s Scheme has
contributed to teaching activi-
ties. By far the largest single
income source for the Key
Centre has been from the host
FinancialsFinancials
ARC KEY CENTRE EXPENDITURETOTAL KEY CENTRE INCOME FROM ALL SOURCES - TOTAL $1,940,666.