Structural investigation of GaN powders thermally annealed at various temperatures

Abstract

In this study we have investigated the change of structural properties for GaN powders annealed in an NH:(3) atmosphere at temperatures of 850. 950, 1050 and 1150 degreesC for 2 hours, by using Scanning Electron Microscopy(SEM), X-ray diffract ion (XRD). neutron diffraction(ND), mid Raman scattering. GaN powders annealed in a N-2 atmosphere at 1050 degreesC for 2 hours was prepared to compare the results with those annealed in an NH3 atmosphere. SEM images shows the GAN powders are of the form of aggregates composed of nano-GaN particles. All XRD). ND mid Hainan scattering peaks from the samples annealed in an NH: atmosphere become stronger and narrower as, annealing temperature increases. The nitrogen-deficient phases such ts Ga2O3 and Ga2H were observed in the sample annealed at 1050 degreesC in a N2 atmosphere, but such nitrogen-deficient phases was absent in the GaN powders annealed in an NH3, atmosphere. It is suggested in this study that the optimal annealing condition of GaN powders for the preparation of the growth, of GaN substates is the annealing at temperatures higher than 1150 degreesC in a NH3 atmosphere.