Theoretical evidence for efficient p-type doping of GaN using beryllium

Ab initio calculations predict that Be is a shallow acceptor in GaN. Its thermal ionization energy is 0.06 eV in wurtzite GaN; the level is valence resonant in the zincblende phase. Be incorporation is severely limited by the formation of Be3N2. It is shown, however, that co-incorporation with reactive species can enhance the solubility. H-assisted incorporation should lead to high doping levels in metal-organic-chemical-vapor deposition growth after post-growth annealing at about 850 K. Be-O co-incorporation produces high Be and O concentrations at molecular beam epitaxy growth temperatures. (C) 1997 American Institute of Physics.