Growth and conversion of β-Ga2O3 nanobelts into GaN nanowires via catalyst-free chemical vapor deposition technique

High-quality gallium nitride (GaN) nanowires (NWs) were successfully synthesized in two steps without the aid of any foreign catalyst. Initially, Ga2O3 nanobelts (NBs) were grown on sapphire substrates via the thermal evaporation of GaN at 1150 degrees C. The NBs exhibited clear peaks in the X-ray diffraction spectrum corresponding to the monoclinic beta-Ga2O3. Nitridation at 1000 degrees C efficiently converted beta-Ga2O3 into one-dimensional GaN NWs. X-ray diffraction analysis confirmed the synthesized nanowires of GaN with hexagonal wurtzite-type crystal structure. Field emission scanning electron microscopy (FESEM) observations revealed that the grown nanowires have a curvature shape with diameters ranging from 30 to 160 nm and lengths up to several micrometers. Photoluminescence studies of GaN NWs showed the presence of a band edge emission is near 3.306 eV and a red luminescence peak at 1.87 eV. Raman scattering analysis reveals that GaN NWs have vibrational modes. The kinetics of nitridation from beta-Ga2O3 NBs to wurtzite GaN NWs in an NH3 atmosphere is also presented. (C) 2012 Elsevier Ltd. All rights reserved.