Interband transitions of InAsxSb1-x alloy films

Abstract

We report pseudodielectric-function spectra from 1.5 to 6.0 eV of InAsxSb1-x ternary alloys obtained by spectroscopic ellipsometry. Energies of the E-1, E-1+Delta(1), E'(0), E'(0)+Delta'(0), E-2, E-2+Delta(2), E'(2), E'(2)+Delta(2), and E'(1) critical points (CPs) were obtained from numerically calculated second derivatives, and identifications established by band-structure calculations using the linear augmented Slater-type orbital method. The E-2, E-2+Delta(2), E'(2), and E'(2)+Delta(2) CP structures cross with increasing As-composition. Two saddle-point transitions, Delta(cu)(5)-Delta(vu)(5) and Delta(cl)(5)-Delta(vu)(5), are found for InSb. (C) 2009 American Institute of Physics. [doi:10.1063/1.3216056]