Optical properties of AlAsxSb1-x alloys determined by in situ ellipsometry

Abstract

We report pseudodielectric function data <epsilon > = <epsilon(1)> + i <epsilon(2)> from 0.74 to 6.48 eV of oxide-free AlAsSb alloys that are the closest representation to date of the intrinsic bulk dielectric response epsilon of the material. Measurements were performed on 1.3 mu m thick films grown on (001) GaAs substrates by molecular beam epitaxy. Data were obtained with the films in situ to avoid oxidation artifacts. Critical-point structures were identified by band-structure calculations done with the linear augmented Slater-type orbital method. Crossings of transitions at the Gamma- and X-points and the Gamma- and L-points with composition were observed. (C) 2013 AIP Publishing LLC.