Structural and electronic data were presented which indicated that the predominant defects in material which had been grown at low temperatures, by means of molecular beam epitaxy, were As antisites (AsGa) and Ga vacancies (VGa); with negligible numbers of As interstitials (Asi). It was shown that the change in lattice parameter was related to the concentration of AsGa, and that this defect alone could account for the lattice expansion. It was also shown that the total concentration of AsGa exhibited a characteristic second-power dependence, upon the concentration of AsGa in the positive charge state, in material which had been grown at various temperatures. This could be explained if it were assumed that VGa defects were the acceptors that were responsible for carrier compensation. The results were consistent with most experimental results, and with theoretical calculations of defect formation energies. These conclusions were also expected to be true of As-rich bulk GaAs.

X.Liu, A.Prasad, J.Nishio, E.R.Weber, Z.Liliental-Weber, W.Walukiewicz: Applied Physics Letters, 1995, 67[2], 279-81