Optical Constants of In1-xGaxSb Ternary Alloys: Experiment and Modeling

The optical response of In1-x Ga x Sb ternary alloys in the 1.5-5.4-eV photon-energy range at room temperature is measured by spectroscopic ellipsometry (SE). The measured SE data show distinct structures at energies of the E 1, E 1+Δ1, E 0 ′, E 0 ′+Δ0 ′, E 2 and E 1 ′ critical points. These spectra are analyzed on the basis of a simplified model of interband transitions. The model proposed here enables us to obtain the optical response in In1-x Ga x Sb alloys of arbitrary composition (x) and photon energy (E=ω). Results of the surface-treatment effect on the pseudodielectric functions are also presented.