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Journal of Crystal Growth

Year: 2009  |  Volume: 311  |  Issue: 10  |  Page No.: 2982 - 2986

Nature of luminescence and strain in gallium nitride nanowires

M.A. Mastro, S. Maximenko, M. Gowda, B.S. Simpkins, P.E. Pehrsson, J.P. Long, A.J. Makinen, J.A. Freitas Jr., J.K. Hite, C.R. Eddy Jr. and J. Kim

Abstract

Photo- and cathodo-luminescence measurements of a variable-diameter ensemble of GaN nanowires revealed a diameter-dependent, spectral emission distribution between 350 nm and 850 nm. Spectral analysis indicated that wires with a diameter less than 400 nm were dominated by a yellow luminescence with a weaker near UV/violet emission also present. Examination of this ensemble showed that there was a general trend in the ratio of near-UV-to-yellow emission intensities with increasing nanowire diameter. Additionally, a broad green emission appears in the nanowires with a diameter above approximately 200& nm. A calculation based on the nanoheteroepitaxy model indicates that this diameter represents a transitional thickness where strain is relieved by defect formation mechanisms with a characteristic green emission.

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