Interband transitions and dielectric functions of InGaSb alloys

Abstract

We report pseudodielectric functions of In1-xGaxSb ternary alloy films from 1.5 to 6.0 eV determined by spectroscopic ellipsometry. Artifacts were minimized by real-time assessment of overlayer removal, leading to accurate representations of the bulk dielectric responses of these materials. Critical-point (CP) energies were obtained from numerically calculated second energy derivatives, and their Brillouin-zone origins identified by band-structure calculations. The E-2' and E-2+Delta(2) CP energies cross with increasing In content as a result of increasing spin-orbit splitting Delta(2). (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4795622]