The slow positron technique was used to study undoped and Be-doped samples, and thereby determine the effect of Be upon the creation and migration of Ga vacancies, VGa, during annealing. It was deduced that a VGa mono-vacancy which was created in Be-doped material resulted in an enhanced Coulombic interaction between an As vacancy, VAs, and a Be acceptor, BeGa. In the case of undoped material, the formation of di-vacancies, VGa-VAs, predominated. The migration length of the vacancies was shorter in Be-doped material than in undoped material. It was therefore suggested that Ga interstitials, IGa, existed in the Be-diffused layer and interacted with VGa which were introduced from the surface. It was suggested that a kick-out mechanism governed Be diffusion in this material.

J.L.Lee, L.Wei, S.Tanigawa, M.Kawabe: Journal of Applied Physics, 1991, 69[9], 6364-3