Monochromatic cathodoluminescence images of threading dislocations in Si-doped n-GaN were observed by using the transmission electron microscopy cathodoluminescence technique. The dependences of the contrast and the full-width at half-maximum of the dislocation image upon sample thickness, accelerating voltage and temperature were studied. The cathodoluminescence spectra were measured at various temperatures and were analyzed with regard to the band-edge emission used for the cathodoluminescence imaging. The observation showed that the full-width at half-maximum of the dislocation contrast increased monotonically with sample thickness and decreased with acceleratingvoltage. This agreed qualitatively with the behavior expected from theory. On the other hand, the temperature dependence of the full-width at half-maximum exhibited an anomalous behavior. This dependence could be explained by the mobility and lifetime of holes as a function of temperature.

Contrast Analysis of Dislocation Images in TEM-Cathodoluminescence Technique. D.Nakaji, V.Grillo, N.Yamamoto, T.Mukai: Journal of Electron Microscopy, 2005, 54[3], 223-30