international journal of science, engineering and technology research...

International Journal of Science, Engineering and Technology Research (IJSETR), Volume 3, Issue 2, February 2014

173 ISSN: 2278 – 7798 All Rights Reserved © 2014 IJSETR

Study the Effect of Proton Irradiation for

Photovoltaic Cells Characteristics in LEO Orbit

Osama A. Oraby1*

, Mohamed F. El-Kordy1,

Hanaa T. El-Madany2, Faten H. Fahmy

2,

1Department of Electronics and Communications, Faculty of Electronic Engineering,

Menofia University, Menouf 32951, Egypt 2Electronics Research Institute, National Research Center Building, Cairo, Egypt

*E-mail: [email protected]

Abstract- Protons can present a hazard to both manned

spacecraft and to the sensitive components in satellite sub system

and instrumentation such as photovoltaic cells. This pair

proposed the theoretical I-V characteristic carve for 10 MeV’

protons with fluence from 108 to 1012 p/cm2 in LEO orbit in

space. Also this paper investigates the behavior of the electrical

parameters of photovoltaic cells. Furthermore, the development

of short circuit current (isc,) and open circuit voltage (Vsc) which

gives maximum power at the same equation order (n) repaired to

LEO orbit. The mathematical formula far the theoretical I-V

characteristic curve from 108 to 1012 p/cm2 and the threshold

level are obtained. in addition, the study the electrical parameters

(Isc, Voc, Pmax, and F.F) as a function of proton fluence are

presented, Also, the comparison between the effect of 10 MeV

protons before and after irradiation is studied.

Index Terms- Proton effects, Photoltaic cell, LEO orbit, and

circuit voltage.

I. INTROBUCTION

M. Imaizumi [1] proposed a model for high energy and high

fluence proton irradiation of Si solar cells which explains

the anomalous increase in he and decrease in Voc followed by abrupt decrease of Ioc, and cell failure, induced by high

fluence proton irradiation. The Isc. increase and the Voc,

decrease can be explained by depletion region broadening.

The abrupt cell failure can he explained by a decrease in

carrier concentration and consequent increase in the

resistively of the base layer. The anomalous change in QE

can be explained by the generation of a donor-type defect

level with proton irradiation and conduction-type

conversion.

Wang Kong [2] reports the high-energy proton irradiation

effects on GaAs/Ge space solar cells. The solar cells were irradiated by protons with energy of 5-20MeV at a Iluence

ranging from I x109 to 7x1013cm-2 and then their electric

parameters were measured at AM0. It was shown that the

Isc; Voc and Pmax, degrade as the fluence increases,

respectively, but the degradation rates of 4. isc , voc and Pmax,.

decrease as the proton energy increases, and the degradation

is relative to proton irradiation-induced defect Ec-0.41 eV in

irradiated GaAs/Ge cells.

M. Alurralde [3] developed art experimental facility to

measure the current voltage characteristic curve of

crystalline silicon solar cells, the cells were irradiated with

10 MeV protons and fluenee between 108 and 1013 p/cm2. Furthermore, theoretical simulations were performed to

establish the relation between the variation of the electrical

parameters and the degradation of the lifetime of minority

carriers in the base. Also he discussed a proposal of new

model of radiation damage for silicon solar cells.

In this paper the theoretical 1-V characteristic curve of

crystalline silicon solar cells used in LEO orbit in space

after irradiation with 10 MeV protons and fluenee between

108 and 1012 p/cm2 has been studied, Also, the mathematical

equation for each case of fluence is obtained.

II. PROBLEM FORMULATION

The solar cells used in space environment are subjected to

bombardment of charged particles of a wide energy range

This bombardment introduces defects in the constituent

materials of the cells and, consequently, deteriorates its

electronic properties. Radiation damage tests, performed

under controlled and normalized conditions, allow studying

the resistance of the photovoltaic (PV) devices to the space environment and predicting their performance at the end of

life (EOL). Therefore, tests are very useful because they

allow a proper design, of the modules for a satellite mission.

Main sources of radiation at affecting PV modules are

protons and electrons trapped by the terrestrial magnetic

field and protons. coming from the Sun, the particle flux

depending on the orbit of the mission. Other sources of

damage are neutrons and 7-rays: these are not relevant in

space, but useful for characterization purposes. The

radiation damage in satellites at low attitude orbits (lower

than 800 km) or in the high altitude ones (5000 km or

higher) is mainly produced by protons (close to 90% of damage). Hence, it is important to evaluate the damage

production using these particles in the experiments on earth.

For satellite applications, the high energy particle radiation

in outer space produces defects in semiconductors that cause

a reduction in solar cell power output Assessing the

expected useful life of the space solar-cell power plant is

important [4]. The interested problem is to obtain the

theoretical equations of 1-V characteristic curve of silicon

solar cell after irradiation with 10 MeV protons and fluenee

between 108 and 1012 p/cm2. The absolute error and the

electrical parameters (short circuit current (Isc) open circuit voltage (Voc) Maximum power (Pmax), and fill factor (FF)

will be studied for each case in details, So, it is too

important to study the perfect theoretical characteristic curve

by fitting the experimental data and the mathematical

equation are obtained which not previously studied before.

The obtained electrical parameters under proton irradiation

are necessary to improve the operation in LEO orbit in

space.



III. RESULTS AND DISCUSSIONS

III. 1. CHARACTERISTIC CURVE DISCUSSIONS

The experimental data of the I-V characteristic curve of

crystalline silicon solar cells after irradiation with 10 MeV

protons and fluence between l08 and 1012 p/cm2 is obtained

from [3], so curve fitting using Matlab program is applied to

obtain the theoretical 1-V characteristic curve. Figure l to

Fig. 5 indicate the theoretical I-V characteristic curve of the

degradation of crystalline silicon solar cell when irradiated

with 108 p/cm2 the equation order(n) varied front 4 to 8

respectively. From these obtained results illustrated in these

figures, it is noticed that there is a large error between the theoretical and experimental results for n=4 and 8

respectively. The obtained theoretical results is nearly

similar to the experimental results for n=5 and 7 as depicted

in Fig. 2 and Fig. 4 respectively. While Fig. 3 shows that the

theoretical results is near to the experimental results so, it is

the perfect theoretical curve for equation order n=6, Thus

the mathematical formulator the optimum 1-V characteristic

curve for 108 p/cm2 curve is given as follows:

I = -156 .6227 V6 + 243 .8975 V5 - 146 .4676 V4 + 41.8778

V3 -5.649 V2 + 0.2794 V +0.096 (1)

Where I is the current of photovoltaic cells, and V is the voltage of photovoltaic cells.

Figure.6 to Fig. 9 shows the theoretical I-V characteristic

curve of the degradation of crystalline silicon solar cell with

10Mev proton and fluence between 109 to 1012 p/cm2 as the

equation order n=6, It is seen from obtained results that the

optimum I-V characteristic curve occurs for n=6. The

mathematical formula for the optimum I-V characteristic

curve for 109 to 1012 p/cm2 respectively is given as follows:

I = -154.2322 V6 +229.1504 V5 -131.154 V4 + 36.0069V3

- 4.756V2 + 0.2331V+0.094 (2)

I = -92.7883V6 +1119307V5 - 49.7737V4 +10S253V3

- 0.921 4V2 + 0.0203V + 0.0921 (3) I=-113.7362V6+131.2421V5-55.3297V4+10.1986V3

-0.7545V2+0.0012V+0.079 (4)

I = -55.5576V6 + 30.5736V5 + 3.8181V4 - 4.6736V2

+ 0.7944V2 - 0.0522V + 0.06l (5)

III. 2. ERROR ANALYSIS AND DISCUSSIONS

Figure 10 and 15 indicate the absolute error as a function of

the PV output voltage for 108 p/cm2 and 109 p/cm2 respectively.

In the case of 108 p/cm2 and the output voltage = 0:384 V,

the absolute error is nearly between 0 up to 9 x 10-4 for n=6.

While it has a value of 2 x l0-4 up to 2 x 10-3 for n = 5 and 0

up to 5 x 10-3 for n=7. On the other hand, for 109 p/cm2 and

V= 0 V: 0.407 V, the absolute error is between 0 up to 7 x

10-4 for tell. While it has a value of 10-4 up to 2x10-3 for n=5

and 0 up to 5 x 10-4 for n=7. It s seen that the best IV

characteristic curve for 108 p/cm2 to 1012 p/cm2 has been

occurred for n= 6 as a result of the minimum absolute error

achieved at n=6.

III. 3. SIMULATION ANALYSIS OF THE ELECTRICAL

PARAMETERS

Figure 12 to 15 indicates the solar cell electrical parameters,

1sc, Poc, and F F at different equation orders (n) and fluence

between 108 and 1012 p/cm2. Its clearly from simulated

results that the short circuit current varies with the equation

order where noticeable increasing in Isc values occurs until

n=6 while Isc reaches to steady state values for higher orders

(n=7 to 9). From Fig. 13, it is seen that Voc. decreases

smoothly until ie6 but an increase in its value occurs gradually with higher order. Figure. 14 shows that .Pmax

increases rapidly until tell but a clear reaches to steady state

for higher order n>6, Figure 15 shows that the fill factor

(FE) increases until n=4 and decreases with a value FE>0.7

for equation order n>4, While a noticeable decrease with a

value nearly F.F<0.7 for higher order n>6. Thus it is clear

that the optimum electrical parameters (values and equation)

occurs at equation order n=6 for fluence 108 to 1012 p/cm2.

The variation of the maximum output power value of silicon

solar cells with the output voltage when irradiated from l08

to 1012 p/cm2 is indicted in Fig. 16. From this figure it’s

clear that the output power occurs at l08 p/cm2 while the lowest value of output power achieved for 1012 p/cm2,

III. 4. THE THRESHOLD LEVEL DISCUSSION

It is found from Fig. 10 and 12 to 15 that the threshold

level occurs for equation order n=6 for different flunces for

108 to 1012 p/cm2 because of large losses in the theoretical

results occurs for n>6.

3.5 THE ELECTRICAL PARAMETERS AND COMPARISON PF 1-V CHARACTERISTICS

Figure 17 shows the effect of proton fluence on the

electrical parameters. It is noticed that a decrease of the

electrical parameters of solar cell with an increase of fluence

of proton radiation. The electrical parameters which reach to

the highest values at 10 p/cm2 while the lowest values at

1012 p/cm2. Figure 18 studies the comparison between the

theoretical characteristics curve of Si solar cells before and

after irradiation with 10 MeV protons with fluence 108 to

1012 p/cm2. ft is shown that the degradation of the 1-V

characteristic curves decrease with an increase of proton

fluence. The best theoretical characteristic curve at normal sun radiation without 10 MeV protons occurs for equation

order n=7 while the best theoretical characteristic curve after

10 MeV protons irradiation occurs far n=6. Also the

theoretical characteristic curve after irradiation of 10 MeV

protons with fluence 108 p/cm2 is the nearest characteristic

curve to normal sun radiation.

IV. CONCLUSIONS

This paper presents a theoretical I-V characteristic curve of

the photovoltaic solar cells after irradiation of 10 MeV

protons with fluence It 108 to 1012 p/cm2 in LEO orbit in

space. It is found that the optimum theoretical I-V

characteristic curve for each ease of proton radiation for

equation order n=6 as a result of the error reaches nearly

zero for n=6 and the mathematical equations are obtained,

Isc, increases gradually while Voc decreases until n=6 and

Power reaches its maximum value at n=6 So the threshold

level occurs n=6. The electrical parameters for photovoltaic

cell (Isc Voc, and FF) decreases with an increase of proton

fluence, From the comparison study between the degradation of theoretical I-V characteristics curve of Si

solar cells before arid after irradiation with 10 MeV protons

with fluence 108 to 1012 p/cm2, the best values for operation

in LEO orbit are obtained by decreasing the proton fluence

or nearest to the case of normal sun radiation without

10MeV protons.



REFERENCES

[1] M. lmaizumi. M. Yamaguchi, S,J. Taylor, S. Matsuda.

0, Kawasaki, and T. Hisarnatsu, Mechanism for the

Anomalous Degradation of Si Solar Cells Induced by

High-Energy Proton irradiation’. Solar Energy

Materials and Solar Cells Journal Vol. 50, pp 339-344,

1998,

[2] Wang Rong, Quo Zengliang, Zhang Xinghui, and Thai

Zuoxu, ―5—20 MeV Proton Irradiation Effects. on

GaAs/Ge Solar Cells for Space Use‖, Solar Energy

Materials and Solar Cells Journal VoL 77,, pp. 351-357,

2003. [3] M. Alurralde, M. 3. L Tamasi, C. J, Bruno, M. ti.

Martinez Bogado, 1. MA. 3. Fernández Vázquez, J.

Dunn, Schul T, A. A. Burlon, P. Stoliar, and A. 3.

Kreiner, Experimental and Theoretical Radiation

Damage Studies on Crystalline Silicon Solar Cell,

Solar Energy Materials and Solar Cells Journal,

Vol. 82, No.4, pp. 531-542, May 2004.

[4] S. M Sm ―Physics of Semiconductor Devices‖, John

Wiley and Sons, Inc., Chapter 14, PP. 790-838,

1981.

international journal of science, engineering and technology research...

Documents