CLEAN AND OXYGEN COVERED INP(110) SURFACES DIFFERENTIAL REFLECTIVITY

We present surface differential reflectivity results on the polarization dependence of optical transitions and on the oxidation of InP(110) surfaces in the energy range between 2.0 and 4.0 eV. The surface dielectric function has been computed for light electric vector along [110] and [001] directions. Three well defined optical peaks have been detected at the following energies: 2.6 eV (light electric vector along [110] direction), 3.1 eV (unpolarized), and 3.5 eV (light electric vector along [001] direction). Absorption kinetics is analyzed by following the reflectivity variation between 1 X 10(2) and 2 X 10(6) L of molecular oxygen at three selected spectral energies. Several well defined steps of the oxidation process are clearly resolved and discussed in terms of disappearance of intrinsic surface states, creation of acceptor and donor defect states, growth of In2O3.