HREELS and photoemission study of GaSb( [formula omitted])-(1×3) surfaces prepared by optimal atomic hydrogen cleaning

Abstract

High-resolution electron-energy-loss spectroscopy (HREELS) and synchrotron-radiation photoemission spectroscopy (SRPES) have been used to study the Sb-stabilised GaSb(1 0 0)-(1×3) surface prepared by a two-stage low-temperature atomic hydrogen cleaning (AHC) procedure. The use of a maximum annealing temperature of 300 °C avoids the degradation of surface stoichiometry associated with higher annealing temperatures. After AHC at a sample temperature of 100 °C, SRPES results show that all Sb oxides have been removed and only a small amount of Ga oxide remains. Further AHC treatment at 300 °C results in a clean surface with a sharp (1×3) low energy electron diffraction pattern. SRPES results indicate that the surface stoichiometry is identical to that previously found for GaSb(1 0 0)-(1×3) prepared by in situ molecular beam epitaxy. Electron energy-dependent HREEL spectra exhibit a coupled plasmon–phonon mode which has been used to study the electronic structure of the near-surface region. Semi-classical dielectric theory simulations of the HREEL spectra of the clean GaSb(1 0 0)-(1×3) surface indicate no detectable electronic damage or dopant passivation results from the AHC treatment. Valence band SRPES indicates that the surface Fermi level is close to the valence band maximum, suggesting the presence of an inversion layer at the surface.