Dielectric function and critical points of AlP determined by spectroscopic ellipsometry

Abstract

We report the room-temperature dielectric function epsilon of AlP from 0.74 to 6.54 eV obtained by in situ spectroscopic ellipsometry. Measurements were done on a 1.2 mu m thick film grown on (001) GaAs by molecular beam epitaxy, with epsilon extracted using a multilayer parametric model. Critical point energies of features in the epsilon spectra were obtained from numerically calculated second-energy-derivatives, and their Brillouin-zone origins identified by band-structure calculations done using the linear augmented Slater-type orbital method. (C) 2013 Elsevier B.V. All rights reserved.