Single-crystalline wurtzite GaN nanowires and zigzagged nanostructures fabricated by sublimation sandwich method

In this paper, sublimation sandwich method (SSM) was introduced to synthesize high-density wurtzite GaN nanowires using Ga and NH3 as starting reagents. Large-scale straight and zigzagged GaN nanowires with different growth direction were grown on gold-coated 6H-SiC substrates at moderate temperatures. The structure properties of these nanowires were investigated in detail. It is found that zigzagged GaN nanowires have hexagonal cross-section and grow along [0001] direction, whereas straight nanowires with smooth surface grow along [11 (2) over bar0] direction. The growth mechanism of the nanowires follows the vapor-liquid-solid (VLS) mechanism. The Raman scattering spectrum of the nanowires presents some new features. in addition, photoluminescence spectra of a single straight and zigzagged GaN nanowire were collected by near-field scanning optical microscope (NSOM) at room temperature, respectively, which displays completely different optical properties. (C) 2008 Elsevier B.V. All rights reserved.