Mechanism for spontaneous growth of GaN nanowires with molecular beam epitaxy

Published

April 1, 2008

Author(s)

Kristine A. Bertness, Alexana Roshko, Lorelle Mansfield, Todd E. Harvey, Norman A. Sanford

Abstract

Although most semiconductor nanowires are grown via the vapor-liquid-solid mechanism, we present evidence that GaN nanowires form because of thermodynamically driven variations in surface sticking coefficients on different crystallographic planes under certain conditions in molecular beam epitaxy (MBE). Specifically, the wires nucleate spontaneously and then propagate because the sticking coefficient on the (0001) c-plane is higher than on the m-plane {1100} under conditions of high temperature (810-830°C) and high N₂ overpressure. Elemental Ga droplets are unstable under these growth conditions and therefore cannot act as catalytic sites for nanowire growth. This conclusion is based on differences in morphology and growth conditions for GaN nanowires grown with and without catalysts, whether the catalysts are extrinsic metals or Ga droplets. The spontaneous MBE growth of GaN nanowires is therefore shown to be distinct in mechanism from that of the growth of most semiconductor nanowires.

Citation

Journal of Crystal Growth

Volume

310

Pub Type

Journals

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Keywords

GaN, growth mechanism, molecular beam epitaxy, nanowires

Citation

Bertness, K. , Roshko, A. , Mansfield, L. , Harvey, T. and Sanford, N. (2008), Mechanism for spontaneous growth of GaN nanowires with molecular beam epitaxy, Journal of Crystal Growth, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=32797 (Accessed October 27, 2025)