Cathodoluminescence experiments were performed in situ in order to monitor the time-dependence of the ultra-violet luminescence in epitaxial lateral overgrowth specimens. A decrease in the observed intensity and a red-shift of the ultra-violet peak were explained in terms of the introduction and diffusion of non-radiative defects. This led to strain-relaxation of the epilayer, which was initially under compressive strain. Monochromatic ultra-violet and yellow cathodoluminescence images showed that dislocations acted as efficient non-radiative recombination centres, that they were not the cause of the yellow band and did not move under the electron beam.

Defect Diffusion and Strain Relaxation in Epitaxial GaN Laterally Overgrown on (00•1) Sapphire under Low Energy Electron Beam Irradiation. A.Amokrane, S.Dassonneville, B.Sieber, J.L.Farvacque, B.Beaumont, V.Bousquet, P.Gibart, J.D.Ganière, K.Leifer: Journal of Physics - Condensed Matter, 2000, 12[49], 10271-8