Sapphire substrate misorientation effects on GaN nucleation layer properties

We investigate the effects of c-plane sapphire substrate misorientation angle on metalorganic chemical vapor deposition of GaN nucleation layers. The angle from (0 0 0 1) c-plane sapphire was varied between 0.05° and 0.30°, tilted towards the m-plane axis. Structural and optical characterization techniques demonstrate an improvement of surface morphology and crystalline quality of GaN nucleation layers as the miscut angle approaches 0.30°. These results correlate well with our previous study of miscut angle on full light-emitting diode structures.