Optically specular a-plane GaN was grown on r-sapphire substrate by metal–organic chemical vapour deposition. Surface morphology and crystal structure anisotropic behavior related to defects with a specific distribution were characterized by X-ray diffraction and atomic force microscopy. Cathodoluminescence images and depth-profiling spectra showed basal stacking faults related emission at 3.42eV, yellow band emission at 2.25 and 3.00eV emission bands of the a-plane GaN. From the results of cathodoluminescence and transmission electron microscopy, the origin of the blue emission band was attributed to donor–acceptor pair emission correlated with prismatic stacking faults.

Study of the Stacking Faults in a-Plane GaN on r-Plane Sapphire Grown by Metal–Organic Chemical Vapor Deposition. H.Fang, L.W.Sang, W.X.Zhu, H.Long, T.J.Yu, Z.J.Yang, G.Y.Zhang: Journal of Crystal Growth, 2011, 318[1], 423-6