Influence of Disorder Effects on Cd1-xZnxTe Optical Properties

Abstract

In this work we proposed a theoretical expression of the band gap dependence with Zn concentration in Cd1–xnxTe alloys. We used the modified virtual crystal approximation and the tight‐binding parameters, which incorporate compositional disorder as an effective potential. The fitting parameters used were the disorder parameter pc for the alloy and the tight‐binding parameters of each binary compound at room temperature. We found that the theoretical model must include disorder effects in order to describe the bowing of the experimental dependence. The theoretical expression is in good agreement with the quadratic function of the energy gap obtained from the fitting of photoreflectance measurements and from values reported by other authors. The experimental analysis was done on polycrystalline thin films grown over glass substrates by rf sputtering technique.

Energy gaps and optical phonon frequencies in InP1−xSbx

“…According to equation (4), the calculation of ω LO (longitudinal optical phonon frequency) and ω TO (transversal optical phonon frequency) also needs the knowledge of ε 0 which in turn is related to the polarity α p as shown by equations ( 11)- (13). α p is obtained by using relation (7).…”

“…The purpose of this paper is to predict theoretical data for the energy band-gaps of the alloys of interest which may serve to obtain the desired optoelectronic and vibrational properties. Our calculations are based on the empirical pseudopotential method (EPM) within the virtual crystal approximation (VCA), combined with the Harrison [11][12][13][14], a correction to the alloy potential has been introduced so as to make allowance for the compositional disorder.…”

Band parameters for AlAs, InAs and their ternary mixed crystals

“…Although other elaborate approaches may produce better values for the electronic band structures of semi-conducting materials, still the EPM within the VCA offers the simplest, and yet a reasonably accurate, means of obtaining the overall band structure of the alloys. However, at the same time, the VCA is known to lead to band gap bowing parameters that are in disagreement with the experimentally observed values [6][7][8][9], a correction to the alloy potential has been introduced in order to make allowance for the compositional disorder. The zinc-blende polytype is considered as a model system.…”