OPTICAL-CONSTANTS OF CUBIC ZNS

The real (epsilon1) and imaginary (epsilon2) parts of the dielectric function of cubic ZnS have been measured by spectroscopic ellipsometry in the 1.2-5.6 eV photon-energy range at room temperature. The measured dielectric-function spectra reveal distinct structures at energies of E0/(E0+DELTA(o)) critical points. These data are analyzed on the basis of a simplified model of interband transitions. Results are in satisfactory agreement with the experimental data over the entire range of photon energies. Dielectric-related optical constants of cubic ZnS, such as the complex refractive index (n* = n + ik), the absorption coefficient (alpha) and the normal-incidence reflectivity (R), are presented and analyzed.