Orientation control of GaN {1 1 (2)over-bar 2} and {1 0 (1)over-bar (3)over-bar} grown on (1 0 (1)over-bar 0) sapphire by metal-organic vapor phase epitaxy

The growth of semipolar GaN on (1 0 (1) over bar 0) (m-plane) sapphire was investigated by metal-organic vapor phase epitaxy (MOVPE). Most of the layers were polycrystalline with (1 1 (2) over bar 2), {1 0 (1) over bar (3) over bar} and {1 0 (1) over bar 0} as the dominant surface orientations. For incomplete nitridation and recrystallization the {1 0 (1) over bar (3) over bar} orientation was dominant. However, the {1 0 (1) over bar (3) over bar} surface is rough due to twinned crystallites. Growth at lower temperatures and with reduced gas flow velocity results in predominantly {1 1 (2) over bar 2} oriented smooth layers. The orientation was also found to be influenced by the nitridation and recrystallization process. (C) 2010 Elsevier B.V. All rights reserved.