Synthesis of gallium nitride powders and nanowires from gallium oxyhydroxide under a flow of ammonia

Gallium nitride (GaN) powders were synthesized from gallium oxyhydroxide (GaOOH.xH(2)O) which was prepared from aqueous solution of gallium nitrate and urea. The process of conversion of gallium oxyhydroxide to gallium nitride under a flow of ammonia was monitored by XRD and Ga-71 magic-angle spinning (MAS) NMR spectroscopy. Gallium oxyhydroxide turned into alpha-Ga2O3 and then GaN without the phase transformation from alpha- to beta-Ga2O3. Ga-71 MAS NMR and PL spectra revealed that a part of GaN powders obtained above 900 degreesC is nitrogen deficient. GaN nanowires were prepared from a mixture of aluminum oxyhydroxide and gallium oxyhydroxide. The nanowires were grown by sublimation of GaN confined by alumina. (C) 2004 Elsevier B.V. All rights reserved.