Threading dislocations in multiple quantum wells were categorized into 3 types (edge, screw, mixed) and were investigated optically. It was found that the epitaxial lateral overgrowth technique could reduce the densities of all line-defects in a wing region which was several μm wide. Growth steps in the wing region were disturbed by the defects which were left in a seed region, and a complicated structure formed at the surfaces of layers which were grown onto epitaxial lateral overgrowth GaN at low temperatures.

Threading Dislocations and Optical Properties of GaN and GaInN. T.Miyajima, T.Hino, S.Tomiya, K.Yanashima, H.Nakajima, Y.Nanishi, A.Satake, Y.Masumoto, K.Akimoto, T.Kobayashi, M.Ikeda: Physica Status Solidi B, 2001, 228[2], 395-402