► GaN substrates of various crystallographic orientations were obtained by ammonothermal method.
► GaN epilayers were grown on -, -, -, and (20.1)-plane GaN substrates by MOCVD.
► Influence of substrate polishing on the quality of GaN epilayers has been demonstrated.
► MOCVD growth conditions have been optimized for -plane GaN epilayers.
► Optical and structural properties have been compared for -, -, -, and (20.1)-plane GaN epilayers.
Source: Journal of Crystal Growth