Light Emission from Semiconductor Nanowires

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Light Emission from Semiconductor Nanowires
Peidong Yang Department of Chemistry University
of California Berkeley, CA 94720
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Semiconductor Nanowires
? Unique Building blocks for Nanoscale Science
and Technology. ? New Chemistry and Physics
based on size and dimensionality. ? Device
Miniaturization optoelectronics photovoltaics,
thermoelectrics, sensing.
Special Issue on Nanowires Guest Editor Y.
Xia P. Yang March, 2003
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Direct Observation of Vapor-Liquid-Solid Nanowire
Growth
800 deg. In-situ TEM
I II III
Alloying
I
Nucleation
II
Growth
III
Unidirectional growth is the consequence of an
anisotropy in solid-liquid interfacial energy.
Y. Wu et al. J. Am. Chem. Soc. 2001, 123, 3165

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Self-Catalytic GaN Nanowire Growth
1050 deg.
Nano. Lett. In press, 2003
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In-situ GaN Nanowire Growth
Growth Rate 300 nm/s
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TEM Characterization of ZnO Nanowires Grown on
Si(100)
AuZn Alloy Tip
H. Yan et al. Adv. Func. Mater. 12, 323,2002
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2D Quantum Confinement in GaN Nanowire
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Single Crystalline GaN Nanotubes Epitaxial
Casting
J. Goldberger, Nature, 422, 599, 2003
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GaN Nanotubes
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Excellent Optical Quality Single-crystallinity
7K
300K
Energy (eV)
J. Goldberger, Nature, 422, 599, 2003
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Semiconductor Nanowire Microcavities
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Room-temperature UV Nanowire Nanolaser
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Threshold lt 50 kW/cm
M. Huang, S. Mao et al. Science, 292, 1897, 2001.
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(No Transcript)
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Nanowire Waveguide and Laser
Fresnel reflectivity 0.18
Cavity roundtrip time ? 100 fs
J.C. Johnson et al. J. Phys. Chem B 105, 11387
(2001).
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What makes a good nanowire microcavity/laser?
Fractional Mode Power

• ? Highly Facetting/Single Crytstalline
• Long lifetime
• Large Gain
• High-Q
• Lower limit ?/2n

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GaN Nanowire Nanolaser
Nature Materials 1, 101,2002
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Hierarchical Nanowire Architectures coupling
H. Yan et al, JACS, 2003 H. Yan et al. Adv.
Mater. 2003.
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Summary
Synthetic methodology development for
1-dimensional semiconductor nanostructures.
Effect of size and dimensionality in optical,
thermoelectric, mechanical, magnetic and
catalytic properties.
Potential applications, Scale up, Nano-micro
interface.
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Acknowledgements
Postdocs Dr. Heon-Jin Choi Dr. Sang-Kwon
Lee Dr. Christian Hess Dr. Hyunjoon Song Dr.
Yanfeng Zhang Dr. Michael Huang Graduates
Yiying Wu, Franklin Kim, Haoquan Yan, Matthew
Law Rong Fan, Rongrui He, Joshua Goldberger,
Susan Habas, Tev Kuykendall Lori Greene Andrea
Tao Peter Pauzauskie
Collaborators Justin Johnson Prof. Richard
Saykally (Chemistry)
upport DOE DOE-NSE NSF-CAREER NSF-NIRT Dreyfus
Foundation Sloan Foundation Hellman
Foundation Beckman Foundation ACS-PRF 3M Res.
Corp.