Vl. Berkovits et al., Local-field effects in reflectance anisotropy spectra of the (001) surfaceof gallium arsenide, PHYS SOL ST, 43(6), 2001, pp. 1018-1024
Characteristic reflectance anisotropy spectra of the naturally oxidized (00
1) surfaces of GaAs undoped crystals and Ga0.7Al0.3As epitaxial films are m
easured in the energy range 1.5-5.7 eV. The spectra are interpreted in the
framework of the microscopic model proposed for a GaAs(001)/oxide interface
and the reflectance anisotropy (difference) theory developed for a multila
yer medium with a monolayer of atomic dipoles located near one of the inter
faces. The anisotropy of dipole polarizability and the anisotropy of the pl
ane lattice formed by dipoles are taken into account within the unified Gre
en function approach of classical electrodynamics. A good agreement between
the measured and calculated reflectance anisotropy spectra of the oxidized
GaAs(001) surfaces shows that the local field effects at the semiconductor
-oxide interface make the main contribution to these spectra. (C) 2001 MAIK
"Nauka/Interperiodica".