one-dimensional nanostructures as subwavelength optical ... · semiconductor nanowires as...
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Peidong Yang
Department of Chemistry, University of California, Berkeley
Materials Science Division, Lawrence Berkeley National Laboratory
OneOne--Dimensional Nanostructures as Dimensional Nanostructures as Subwavelength Subwavelength
Optical Elements for Photonics IntegrationOptical Elements for Photonics Integration
Pushing the Size Limits of PhotonicsPushing the Size Limits of Photonics
S.Y. Lin et.al. Science 282, 274 (1998).
A. Birner et. al. Adv. Mat. 13, 377 (2001). V.L. Almeida et. al. Nature 431, 1081 (2004).R. Quidant et. al. Phys. Rev. B 69, 81402R (2004).
• Controlling the flow of light in small volumes – optical memory, logic, switching, etc.
Photonic Crystals (>1 μm) Slab/Slot Waveguides (<1 μm) Plasmonics (< 100 nm)
J.C. Krenn et. al. Phil. Trans. R. Soc. Lond. A 362, 739 (2004)Barnes et. al. Nature 424, 824 (2003).
K. Djordjev et. al. IEEE Phot. Technol. Lett., 14, 828 (2002).K.J. Vahala Nature (Insight Review), 424, 839 (2003). M. Paniccia et. al. Topics Appl. Phys., 94, 51 (2004).
OnOn--Chip Photonic IntegrationChip Photonic Integration
SOI fabrication approach
Heterogeneous Integration approachHeterogeneous Integration approach
H. Yan et al. Adv. Func. Mater. 12, 323,2002T. Kuykendall, P. Pauzauskie, et al. Nano. Lett. 3, 1063, 2003.
Single Crystalline, Single Domain, Single Crystalline, Single Domain, FacettingFacetting
VaporVapor--LiquidLiquid--Solid EpitaxySolid Epitaxy
Si Nanowire ArraysSi Nanowire Arrays
ZnO Nanowire ArraysZnO Nanowire Arrays
GaN Nanowire ArraysGaN Nanowire Arrays
P. Yang, Adv. Mater. 15, 353, 2003.Y. Wu et al. Chemistry, Euro. J. 8, 1260, 2002
M. Law et al. Annu. Rev. Mater. Sci. . 34, 83, 2004
Growth Direction ControlGrowth Direction Control
γ-LiAlO2 (100)< 1 1 0 > Alignment: GaN< 1 1 0 > Alignment: GaN
T. Kuykendall, P. Pauzauskie et al. Nature Mater. 3, 528,2004
< 0 0 1 >< 0 0 1 > Alignment: GaNAlignment: GaNSiC or MgO (111)SiC or MgO (111)
Superlattice
Interface within NanowiresInterface within Nanowires
Core-Sheath
Y. Wu et al.Nanolett, 2, 83, 2002. J. Goldberger et al. Nature, 422, 599, 2003 .
H. Choi et al. J. Phys. Chem. B 107, 8721, 2003.
Nanotube
M. Huang et al. Science, 292, 1897, 2001.
Semiconductor Semiconductor Nanowire MicrocavitiesNanowire Microcavities
Lasing Single ZnO NanowireLasing Single ZnO Nanowire
350 360 370 380 390 400 410 420
Wavelength (nm) J.C. Johnson et al. J. Phys. Chem B 105, 11387 (2001).
J. C. Johnson et al. J. Phys. Chem. B, 107, 8816, 2003.
H. Yan et al. Adv. Mater. 2004
)(2
2
λλ
λλ
ddnnL −
=Δ
GaN Nanowire NanolaserGaN Nanowire Nanolaser
Nature Materials 1, 101,2002
)(2
2
λλ
λλ
ddnnL −
=Δ
• Evidence for coherent laser pulses (GaN and ZnO)
Complex farComplex far--field emission patternfield emission pattern
Nanowire microcavity/laser
Highly Facetting/Single Crystalline
Lower limit λ/2n: r > 60 nm
Gth: 400 – 3000 cm-1
High-Q: 500-1500
Lower lasing threshold: ~ 70 nJ/cm2 (sub-ps pulses)
J. Phys. Chem. B, 107, 8816, 2003
Theoretical Simulation: Nanowire Lasers
C. Ning et al. APL, 83, 1237, 2003
th2e VCQ,Lre
Qn ⋅=×π×
=DS2
G
VLC
dVdI
⋅⎟⎠⎞
⎜⎝⎛⋅μ=
~ 50-200 cm2/V.s3181031 −×− cm
GaN Nanowire Transistor: nGaN Nanowire Transistor: n--typetype
Nano. Lett. 3, 1063, 2003.
pp--SOI/ nSOI/ n--GaN Nanowire Matrix LEDGaN Nanowire Matrix LED
H. Yan, J. Goldberger, Unpublished Results
pp--SOI/ nSOI/ n--GaN Nanowire Matrix LEDGaN Nanowire Matrix LED
H. Yan, J. Goldberger, Unpublished Results
Addressable UV LED ArrayAddressable UV LED Array
0.00E+00
5.00E-06
1.00E-05
1.50E-05
2.00E-05
2.50E-05
3.00E-05
3.50E-05
4.00E-05
4.50E-05
5.00E-05
0 2 4 6 8 10 120
20000
40000
60000
300 400 500 600 700 800Wavelength (nm)
Inte
nsity
(a.u
.)
Electroluminescence
Photoluminescence
Subwavelength oxide Nanoribbon Waveguides and Optical Elements
500 nm
Dimensions: Length > 1.5 mm Width 200 – 500 nm Thickness 100 – 300 nm
Aspect ratios > 1000
1 μm
1 μm
1 μm
1 μm
1 μm
Low-Loss Optical Waveguiding
excite
collect50 μm 350 400 450 500 550 600 650 700 750
5 K
300 K
Inte
nsity
(a.u
.)Wavelength (nm)
460 480 500
Inte
nsity
(a.u
.)
Wavelength (nm)
Propagation losses: 1 – 8 db/mm(NSOM)
400 500 600 700 800
Inte
nsity
(a.u
.)
Wavelength (nm)
22.5 kW/cm2
18.3 kW/cm2
11.8 kW/cm2
7.1 kW/cm2
4.7 kW/cm2
2.3 kW/cm2
0.4 kW/cm2
Dimensions: 715 μm x 350 nm x 245 nm
50 μm
500 nm
M. Law and D.J. Sirbuly et al. Science 305, 1269 (2004).
Non-Resonant Waveguiding
Cavity Manipulation
100 μm 25 μm200 nm
10 μm
ZnO nanowire
W tip
Manipulation size limits:
Wires: < 3 μm length< 50 nm dia.
Particles < 50 nm dia.
Used to cut, flip, bend, Used to cut, flip, bend, rotate, position, etc.rotate, position, etc.
3 μm 5 μm 1 μm
Shape Manipulation
300 400 500 600 700 800
PL SnO2
WG SnO2
WG ZnO
PL ZnO
Inte
nsity
(a.u
.)
Wavelength (nm)
Optical Optical HeterojunctionsHeterojunctions: : Evanescent wave coupling
1 μm
ZnO
SnO2
25 μm
Pump
Junction
Collect
The nanoribbon imprints its mode spectrum on the ZnO PL.
Subwavelength Optical Junctions and NetworksSubwavelength Optical Junctions and Networks
~ 50% of light energy couples through junction –evanescent waves
1
2
3
4
25 μm
1 2 & 3 1 & 42
CrossCross--Bar Assembly Bar Assembly –– Coupling Scattered LightCoupling Scattered Light
25 μm
200 nm
1
2
3
4
5
6
7
Pump
Intensity Variations: 1 >> 6 > 4 ≈ 7 > 3 > 5 >2
300 400 500 600 700 800
580 nm
527 nm
514 nm
492 nm
465 nm
Inte
nsity
(a.u
.)
Wavelength (nm)
300 400 500 600 700 800
Inte
nsity
(a.u
.)
Wavelength (nm)
Increasing pump –probe distance
PL
Size Effect on Waveguiding
Short-pass filters:580 nm 375 x 140 nm (0.052 μm2)
527 nm 250 x 225 nm (0.056 μm2)
514 nm 350 x 115 nm (0.040 μm2)
492 nm 280 x 120 nm (0.034 μm2)
465 nm 310 x 100 nm (0.03 μm2)
2/122 )( clco nndV −=λπ
2/122 )(405.2 −− −= clcooffcut nnd λ
π
405.20 <<VSingle-mode operation:
V-parameter:
λcut-off Dimensions
Filtering White Light (MultiFiltering White Light (Multi--Channel)Channel)
210 x 135 nmλcut-off = 478 nm
260 x 175 nmλcut-off = 502 nm
350 x 140 nmλcut-off = 543 nm
single mode cut-off (cylindrical step-index fiber) Diameter (nm)543 nm 274 nm502 nm478 nm
253 nm241 nm
0.05896
Area (um2)
0.05027
0.045617
Exp. Area (um2)0.04900
0.04550
0.02835
Waveguiding Nanowire Laser Pulses Waveguiding Nanowire Laser Pulses -- GaNGaN
350 360 370 380 390 400
10
20
30
40
WG Lasing
GaN Lasing
WG PL
GaN PL
norm
aliz
ed in
tens
ity (a
.u.)
wavelength (nm)
GaN
SnO2
25 μm
ZnO
GaN
SnO2
350 360 370 380 390 400 410
Inte
nsity
(a.u
.)
Wavelength (nm)
ZnO
GaN
Dual Nanowire Laser InjectionDual Nanowire Laser Injection
Wave Mixing?
132213 ωωωωωω −=+=
Detect
50 μm
Waveguiding in Liquids Waveguiding in Liquids –– High Index NanowiresHigh Index Nanowires- Local bio-medicinal probe/spectroscopy (in vivo)- Micro/nanofluidics, PDT, chemical photo-release,
integrated bio-chip, etc.
100 μm
Glycoln = 1.45
Watern = 1.33
25 μm
Excite 442 nm
10 μm
540 μm x 240 nm x 260 nm
• Inject resonant light to induce local fluorescence at the end or along the length of the ribbon.
Local Fluorescence Scheme
• Probe direct or back-guided fluorescence.
3 pL
1 mM R6G
D.J. Sirbuly and M. Law et al. PNAS (2005).
Nanowire Evanescent Subwavelength SpectrometryNanowire Evanescent Subwavelength Spectrometry
400 500 600 700 800
535 nm
Inte
nsity
(a.u
.)
Wavelength (nm)
Dry Ribbon Pure Solvent 50 μM R6G 1.6 mM R6G
Inject broad light source and probe waveguided photons.
Utilize evanescent field to detect molecules. 50 μm
1.6 mM R6G
V ~ 1 pL
430 μm x 240 nm x 260 nm
Detect
Generate PL
sub-picoliter probe volumes
path lengths of 1-50 microns
detection of 103 molecules is achievable
Local Absorption Scheme
Nanowire Evanescent Subwavelength SpectrometryNanowire Evanescent Subwavelength Spectrometry
Semiconductor Nanowires as Semiconductor Nanowires as Subwavelength Photonics IntegrationSubwavelength Photonics Integration
OnOn--Chip Heterogeneous Photonic IntegrationChip Heterogeneous Photonic IntegrationPushing the Size Limits of PhotonicsPushing the Size Limits of Photonics
Precise 1-dimensional nanostructure synthesis and assemblySelf-Organized Optical Cavity
Nanowire based optical cavity, UV coherent light sourcesFrom Fabry-Perot cavity to ring laserFrom optical pumping to light emitting diodes, and laser diodesSubwavelength optical waveguidesOptical waveguiding in solution, interface with microfluidicsSubwavelength optical spectroscopy (absorption, PL…)
Acknowledgements Acknowledgements
Dr. Michael HuangDr. Yiying Wu
Dr. Heonjin ChoiHaoquan YanDr. Justin Johnson (Saykally Group)
Dr. Don SirbulyPeter PauzauskieMatt LawJosh GoldbergerTev Kuykendall
Dr. Alex Maslov (NASA Ames)Collaborators Prof. Richard Saykally (UCB)Dr. Cun-Zheng Ning (NASA Ames)
FundingDOE, NSF, DARPA
Beckman Foundation