Ellipsometric and thermoreflectance spectra of epitaxial InSb films

We have measured spectroscopic-ellipsometry (SE) and thermoreflectance (TR) spectra of epitaxial InSb film sputter-deposited on a (0001) sapphire substrate in the 1.5--5.5-eV photon-energy range at room temperature. These data are analyzed on the basis of a simplified model of the interband transitions. Results are in satisfactory agreement with the experimental data over the entire range of photon energies. The finding definitely links the temperature-induced change in the dielectric function (TR) to the first derivative of the unperturbed dielectric function (SE). The importance of the fractional coefficients {α} and {β} has also been demonstrated for a reliable interpretation of the observed TR line shapes.