In-plane and depth-resolved cathodoluminescence micro-analysis and spectroscopy were used to study the effect of electron injection upon the electromigration and diffusion of native defects and residual impurities in rapidly thermally annealed Mg-doped p-type GaN. During intense electron-beam irradiation (10keV, 80nA), an electric field was generated within the primary beam interaction volume. It was observed that 2 electric field-related effects occurred. One was an increased electron recombination length and a subsequent field-assisted charge spreading which caused the dissociation of Mg-H complexes beyond the interaction volume of the primary electron beam. The other was the thermally assisted electromigration of positively charged mobile defects. This led to the formation of deeper complexes which were highly stable and acted as non-radiative recombination pathways. The diffusion of electron-beam dissociated H was also found to result in the passivation of Mg acceptors beyond the charge recombination volume.

Electron Irradiation-Induced Electromigration and Diffusion of Defects in Mg-Doped GaN. O.Gelhausen, H.N.Klein, M.R.Phillips, E.M.Goldys: Physica Status Solidi B, 2003, 239[2], 310-5