The effect of low-energy electron beam irradiation upon residual H impurities and native defects in activated metal-organic vapor phase epitaxially-grown Mg-doped p-type layers was studied by means of cathodoluminescence micro-analysis and spectroscopy at 80 to 300K. The low-energy electron beam irradiation treatment dissociated (Mg–H)0 complexes to produce, at 300K, a significant increase in a free-to-bound transition (e,Mg0) centered at 3.26eV and, at 80K, to a substantial decrease in a H–Mg donor–acceptor pair emission at 3.27eV. In-plane and depth-resolved cathodoluminescence imaging revealed a direct correlation between the spatial distribution of the injected carriers and the depth and lateral distributions of activated Mg acceptors. This strongly suggested that H dissociation resulted from electron-hole recombination at H defect complexes rather than from heating by the electron beam. The results at 80K indicated that the dissociation of H from (Mg–H)0 complexes was accompanied by the generation of additional defect centers. It was proposed that, following low-energy electron beam irradiation, H did not leave the specimen but instead associated with N vacancies to generate additional recombination channels.

Influence of Low-Energy Electron Beam Irradiation on Defects in Activated Mg-Doped GaN. O.Gelhausen, H.N.Klein, M.R.Phillips, E.M.Goldys: Applied Physics Letters, 2002, 81[20], 3747-9