Threading dislocations in multiple quantum wells and epitaxially lateral overgrown material were categorized into 3 types (edge, screw, mixed) and were investigated optically. It was confirmed, using cathodoluminescence measurements, that not only screw and mixed dislocations but also edge dislocations acted as non-radiative centers. The epitaxial lateral overgrowth technique was able to 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 surface of GaN 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