Nitridation- and Buffer-Layer-Free Growth of [1(1)over-bar00]-Oriented GaN Domains on m-Plane Sapphire Substrates by Using Hydride Vapor Phase Epitaxy

Over a wide range of growth conditions, GaN domains were grown on bare m-plane sapphire substrates by using hydride vapor phase epitaxy (HVPE), and the relation between these growth conditions and three possible preferred crystallographic orientations ([1 (1) over bar 00], [1 (1) over bar0 (3) over bar], [11 (2) over bar2]) of GaN domains was investigated. In contrast with the previous reports by other groups, our results revealed that preferentially [1 (1) over bar 00]-oriented GaN domains were grown without low-temperature nitridation or a buffer layer, and that the growth condition of preferentially [1 (1) over bar 00]-oriented GaN was insensitive to V/III ratio. (C) 2012 The Japan Society of Applied Physics