Ammonothermal synthesis of GaN using Ba(NH2)2 as mineralizer

Abstract

It is demonstrated that hexagonal GaN can be obtained under ammonothermal conditions (125MPa and 723K) using Ba(NH2)2 as mineralizer. The hexagonal wurtzite-type GaN crystallites are several µm in diameter, as examined by scanning electron microscopy. This is to our knowledge the first successful ammonothermal GaN synthesis using an alkaline-earth metal as mineralizer. Ba[Ga(NH2)4]2 was identified as intermediate species in the ammonothermal synthesis process. The formation of h-GaN using Sr(NH2)2 as mineralizer was indicated only at higher temperatures above 1000K.