Ammonothermal GaN: Morphology and properties

Bulk crystals of gallium nitride have been grown using the ammonothermal method. Seeded growth resulted in thick, faceted GaN specimens. The crystal habit was identified and consisted of a hexagonal prism with pyramidal facets. Fast growth rates were observed on the nitrogen face and in the a-direction. The surface morphology and etching characteristics varied by growth sector. These differences have been correlated with characterization by X-ray diffraction, photoluminescence, and secondary ion mass spectroscopy. The material grown on the nitrogen face of the seed was of higher quality than the gallium face growth. The most promising material was grown laterally off the seed in the a-direction.