PULSED-LASER-INDUCED ETCHING OF BR-GAAS(110)

Scanning tunneling microscopy results show that single-layer etch pits are formed by irradiation of Br-covered GaAs(110) using 2.3 eV photon s from a pulsed Nd-YAG laser. The pit morphologies produced in this wa y are very different from those obtained by spontaneous etching at ele vated temperature or by thermal desorption of bromine-saturated surfac es. We explain this laser-induced etching by a combination of short du ration substrate heating and substrate-mediated charge transfer proces ses. Such etching occurs under conditions where surface diffusion of B r is minimal so that the pit profiles reflect the chemisorption struct ures. (C) 1997 Elsevier Science B.V.