Dielectric functions and the interband critical points of InAs0.05Sb0.95 film grown by a modified LPE technique

InAs0.05Sb0.95 film with thickness of 100 μm has been grown by a modified LPE technique, and optical properties of the material have been investigated using spectroscopic-ellipsometry at room temperature within 1.5–4.5 eV. The dielectric function ε(E) spectra that show high-lying interband structure associated with E1, E1+Δ1, and E2 transition have been observed and analyzed on the basis of a simplified model of the interband transitions. Results agree satisfactorily with the experimental data over the entire range of photon energies. The transition energies E1 and E2, the spin–orbit splitting energy Δ1, and the broadening parameters are given, respectively.