SB-INDUCED SURFACE RECONSTRUCTION ON GAAS(001)

Reconstructed surfaces on Sb/GaAs(001) have been investigated in situ by reflection high-energy electron diffraction (RHEED) and core-level photoelectron spectroscopy by heating a sample prepared by depositing Sb on an As-terminated GaAs(001) surface at room temperature (RT). Bef ore Sb desorption, the halo RHEED pattern changes into 1 X 4, 1 X 3, a nd 2 X 4 patterns from RT to 560-degrees-C, which is in contrast to Sb /GaAs(110) that shows only a 1 X 1 pattern. It is found that the GaAs surface with a 2 X 4 pattern is terminated by a monolayer of Sb, and t hat these superstructure changes are caused by As atom desorption foll owed by Sb atom substitution.