Morphologies of GaN single crystals grown from Ga solutions under flowing ammonia

Gallium nitride (GaN) crystals were synthesized by the reaction between gallium-containing solutions and flowing ammonia at temperatures between 900 and 1050 °C under atmospheric pressure. The crystals were colorless or amber with a size up to 1 mm. Two main morphologies were observed: platelet-like and prism-like, which depended on experimental conditions. The observed varieties of the morphology in the cross-section of GaN samples are attributed to a non-uniform distribution of nitrogen species in solution.