Direct observations of individual dopant impurities (SiGa in GaAs, SAs in InAs), and Ga vacancies, VGa, on the (110) cleavage surfaces of III-V compounds were reported. In scanning tunnelling microscopic images under low sample bias voltages, the charged dopants and surface vacancies exhibited delocalized features which were seen as protrusions or depressions that extended over several lattice sites on the (110) face. It was concluded that this approach offered new possibilities for studying individual defects in compound semiconductors at the atomic scale.

S.Gwo, S.Miwa, H.Ohno, J.F.Fan, H.Tokumoto: Materials Science Forum, 1995, 196-201 1949-54