Influence of disorder effects on Cd1-xZnxTe optical properties

In this work we proposed a theoretical expression of the band gap dependenc e with Zn concentration in Cd(1-x)n(x)Te alloys. We used the modified virtu al crystal approximation and the tight-binding parameters, which incorporat e compositional disorder as an effective potential. The fitting parameters used were the disorder parameter p(c) for the alloy and the tight-binding p arameters of each binary compound at room temperature. We found that the th eoretical model must include disorder effects in order to describe the bowi ng of the experimental dependence. The theoretical expression is in good ag reement with the quadratic function of the energy gap obtained from the fit ting of photoreflectance measurements and from values reported by other aut hors. The experimental analysis was done on polycrystalline thin films grow n over glass substrates by rf sputtering technique.