The GaN was grown onto a random-cone patterned sapphire substrate, prepared by natural lithography using metalorganic vapour phase epitaxy. Scanning and transmission electron microscopy was used to investigate the growth mode of the GaN layer on the random-cone patterned sapphire substrate. Some dislocations which were generated at the GaN/sapphire interface were bent, and annihilated via lateral overgrowth and selective area growth. The dislocation density decreased with increasing cone density.

Growth of GaN Layer and Characterization of Light-Emitting Diode Using Random-Cone Patterned Sapphire Substrate. N.Okada, T.Murata, K.Tadatomo, H.C.Chang, K.Watanabe: Japanese Journal of Applied Physics, 2009, 48[12], 122103