Nitridation-and buffer-layer-free growth of 1[100]-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[100]; =1[10]3 ]; =11[22] of GaN domains was investigated. In contrast with the previous reports by other groups, our results revealed that preferentially =1[100]-oriented GaN domains were grown without low-temperature nitridation or a buffer layer, and that the growth condition of preferentially =1[100]-oriented GaN was insensitive to V/III ratio.