Optical Constants of Zn1-xCdxTe Ternary Alloys: Experiment and Modeling

The optical spectra of Zn1-x Cd x Te ternary alloys in the 1.1-5.6-eV photon-energy range at room temperature have been measured by spectroscopic ellipsometry (SE). The optical constants reported here are the complex dielectric constant (ε=ε1+iε2), complex refractive index (n *=n+ik), absorption coefficient (α) and normal-incidence reflectivity (R). The measured data are analyzed on the basis of a simplified model of the interband transitions. The experimental data reveal distinct structures in the optical spectra at energies of the E 0, E 0+Δ0, E 1, E 1+Δ1 and E 2 transitions, and are in reasonable agreement with the theoretical model. The model proposed here enables us to obtain the optical response in Zn1-x Cd x Te alloys of arbitrary composition (x) and photon energy (E=ω).