Surface Core-Level Binding-Energy Shifts for GaAs(110) and GaSb(110)

Surface 3d and 4d core-levell binding-energy shifts have been resolved in photoemission from GaAs(110) and GaSb(110), which yield new information on semiconductor surface reconstruction. The shifts ( approx 0.3 eV) are toward higher (lower) binding energies for the surface cations (anions), in agreement with a simple model involving the known surface relaxation of GaAs(110) with a geometry-dependent initial-state charge transfer. Surface core-excitation binding energies, core-level widths, escape depths, etc., are re-evaluated.16 refs.--AA