Temperature dependence of the dielectric function and critical-point energies of InAs

Abstract

We report the complex dielectric function of InAs for energies from 0.74 to 6.54 eV and temperatures from 22 to 675 K. The complex dielectric function was determined by using spectroscopic ellipsometry. The critical-point (CP) structures at low temperatures are blue-shifted and are sharpened significantly relative to those observed at high temperatures, which can be explained by using the reduction of the electron-phonon interaction and the thermal expansion. The CP energies are determined by using lineshape fittings to numerically calculated second energy derivatives of the dielectric function. The obtained CP energies are fit to a phenomenological expression that contains the Bose-Einstein statistical factor and to a linear equation.