The role of dislocations, in the luminescence of material which had been grown onto sapphire by using metalorganic chemical vapor deposition, was investigated by means of cathodoluminescence and atomic force microscopy. The cathodoluminescence emission area, and dark spots between the layers of InGaN/GaN single quantum well and multiple quantum well structures, exhibited a completely one-to-one correspondence. The results indicated that dislocations in InGaN acted as non-radiative recombination centers. It was also confirmed that phase separation was caused by spiral growth due to mixed dislocations.

Role of dislocations in InGaN phase separation T.Sugahara, M.Hao, T.Wang, D.Nakagawa, Y.Naoi, K.Nishino, S.Sakai: Japanese Journal of Applied Physics - 2, 1998, 37[10B], L1195-8