The effect of the number of quantum-well pairs upon the interfacial structure of multiple quantum wells, as grown by means of low-pressure metal-organic vapour-phase epitaxy, was examined. As the number of pairs increased, it was noted that In-rich InGaN precipitates were more easily detected by using cross-sectional transmission electron microscopy. The intensity of the photoluminescence peak was decreased, and the peak was red-shifted with increasing number of pairs. The use of X-ray diffraction revealed that the interfacial structure between InGaN and GaN also deteriorated with increasing number of pairs. The results were attributed to the relaxation of accumulated strain by dislocations which were introduced by an increase in the total thickness of the multiple quantum wells with increasing number of pairs. The results suggested that defects such as dislocations facilitated the formation of In-rich phases in the InGaN layers.

Structural and Optical Properties of InGaN/GaN Multiple Quantum Wells - the Effect of the Number of InGaN/GaN Pairs. D.J.Kim, Y.T.Moon, K.M.Song, C.J.Choi, Y.W.Ok, T.Y.Seong, S.J.Park: Journal of Crystal Growth, 2000, 221, 368-72