The correlation between the type of dislocation and the photoluminescence characteristics was investigated for various Si dopant concentrations in GaN films. A differing broadening behavior of symmetrical and asymmetrical Bragg peaks, as a function of carrier concentration, provided qualitative evidence that the type of threading dislocations generated in GaN layers was strongly dependent upon the Si doping level. Photoluminescence spectra, in conjunction with X-ray rocking curve measurements, suggested that the yellow luminescence associated with deep levels was more strongly related to edge dislocations than to screw or mixed ones.

Correlation between the Type of Threading Dislocations and Photoluminescence Characteristics at Different Doping Concentrations of Si in GaN Films. C.Kim, S.Kim, Y.Choi, S.J.Leem: Journal of Applied Physics, 2002, 92[10], 6343-5