Reaction mechanism for the ammonolysis of β-gallium oxide to gallium nitride

Abstract

The reaction mechanism for the ammonolysis of β-gallium oxide (β-Ga₂O₃) to gallium nitride (GaN) was elucidated by observing the morphology of microsized β-Ga₂O₃ single crystals with a distinct shape under a flow of ammonia (NH₃) and hydrogen (H₂) at elevated temperatures. The morphology of the microsized β-Ga₂O₃ single crystals grown on the c-plane sapphire by the thermal annealing of gallium sulfide, was not retained after calcination under a flow of NH₃ and H₂. These microstructural observations strongly support that the ammonolysis of β-Ga₂O₃ to GaN proceeds through gaseous Ga₂O, and that the rate of the reduction of β-Ga₂O₃ to Ga₂O is slower than that of the nitridation of Ga₂O to GaN.