Low pressure synthesis of bulk, polycrystalline gallium nitride

Thick films of polycrystalline GaN were grown at low pressures by direct reaction of atomic nitrogen with liquid Ga without the presence of a substrate. The crystals were confirmed to be wurtzitic GaN by x-ray diffraction, transmission electron microscopy, Raman spectroscopy, and elemental analysis. Photoluminescence spectra showed near band edge peaks and broad yellow band emission at both 298 and 10 K. The results show that atomic nitrogen is an attractive alternative to high pressure N-2 for the saturation of liquid gallium with nitrogen for the synthesis of bulk GaN. (C) 1997 American Institute of Physics.