Reaction ofI2with the (001) surfaces of GaAs, InAs, and InSb. I. Chemical interaction with the substrate

InAs(001)-c(8×2), InSb(001)-c(8×2), and several reconstructions of GaAs(001) are exposed at room temperature to iodine molecules (${\mathrm{I}}_2$). Low-energy electron diffraction (LEED) and synchrotron soft x-ray photoelectron spectroscopy (SXPS) are employed to study the surfaces as a function of ${\mathrm{I}}_2$ dose and sample anneal. In the exposure range studied, GaAs and InAs become saturated with ${\mathrm{I}}_2$, resulting in removal of the clean surface reconstruction and the formation of a very strong 1×1 LEED pattern. Iodine bonds primarily to the dominant elemental species present on the clean surface, whether it is a group-III or -V element. The InSb(001)-c(8×2) reconstruction is also removed by ${\mathrm{I}}_2$ adsorption, and a strong 1×1 LEED pattern is formed. SXPS data, in conjunction with scanning tunneling microscopy images, however, reveal that InSb(001)-c(8×2) does not saturate at room temperature, but is instead etched with a preferential loss of In. Heating the iodine-covered group-III-rich InAs(001)-c(8×2) and InSb(001)-c(8×2) surfaces causes removal of the iodine overlayer and transformation to a group-V-rich reconstruction. When the iodine-covered As-rich GaAs(001)-c(2×8) surface is heated to remove iodine, however, the c(2×8) reconstruction is simply regenerated. © 1996 The American Physical Society.