Synthesis of gallium nitride by ammonia injection into gallium melt

Gallium nitride (GaN) was synthesized by injecting ammonia gas into molten gallium at 900-980 degrees C under atmospheric pressure. A large amount of GaN powder was reproducibly obtained using a simple apparatus. The synthesized powder was characterized by scanning electron microscopy, X-ray diffraction, photoluminescence and energy dispersive X-ray spectroscopy, and was found to consist of fine crystals of hexagonal GaN of good quality. The total of GaN obtained was far more than the amount calculated from expected saturation solubility in the Ga melt at that temperature. We speculate that the GaN crystals were largely formed by direct reaction between Ga and the gaseous N source at the surface of the NH, bubbles in the melt. GaN synthesized by this method may be useful as a starting material for bulk growth. (C) 1999 Elsevier Science B.V. All rights reserved.