GAN SYNTHESIS BY AMMONOTHERMAL METHOD

It is shown that ammonothermal method can be successfully used to synt hesize GaN powder of good crystallographic quality from ammonia soluti on at high pressure and a moderate temperature. The size of obtained G aN powder grains was of a few micrometers. The improvement of the powd er crystalline quality (examined by X-ray rocking curve, scanning elec tron microscopy and luminescence measurements) with increasing molar p roportion of mineralizer was observed. It was therefore possible to co nclude that high molar proportion of mineralizer in ammonia solution p lays a crucial role in the polycrystal growth process. Visible lumines cence of high efficiency from the GaN powder was found.