The effect of low-energy electron-beam irradiation upon the stability of acceptor-H complexes in Mg-doped material was studied by means of infra-red optical spectroscopy. It was found that Mg–H pairs began to break up under 25keV electron-beam exposure at doses of a few mC/cm2. However, even after long exposures, about half of the acceptor-H pairs remained unaffected by the electrons. By using Mg-doped samples that were vacuum-annealed and exposed to D gas, it was shown that there was a large (about 5 times) isotopic shift in the beam-induced de-bonding rate of the acceptor-H complexes. The H and D remained in the material during the treatments, and Mg–H or Mg–D re-formed during post-irradiation annealing.

Isotope Effects on the Rate of Electron-Beam Dissociation of Mg–H Complexes in GaN. C.H.Seager, S.M.Myers, B.Vaandrager, J.S.Nelson: Applied Physics Letters, 2002, 80[15], 2693-5