Native defects in non-stoichiometric layers, grown at low temperatures by molecular-beam epitaxy of GaAs doped with Be, were investigated. Vacancies, VGa, were found in all layers by means of positron annihilation. The VGa concentration was independent of the degree of Be-doping. This contradicted the existing belief that it decreased. At the same time, the concentration of As antisite defects, AsGa, was measured via optical absorption techniques. The same relationship was found, between VGa and AsGa concentrations, as had been reported for undoped low-temperature molecular beam epitaxial GaAs. Therefore, Be doping had no significant effect upon the incorporation of native point defects into low-temperature molecular beam epitaxial GaAs. The thermal stability of such material thus had to be explained in another way.

Does Beryllium Doping Suppress the Formation of Ga Vacancies in Nonstoichiometric GaAs Layers Grown at Low Temperatures? J.Gebauer, R.Zhao, P.Specht, E.R.Weber, F.Börner, F.Redmann, R.Krause-Rehberg: Applied Physics Letters, 2001, 79[26], 4313-5