Temperature dependence of the energy gap of zinc-blende CdSe and Cd1−xZnxSe epitaxial layers

Abstract
The temperature dependence of the energy gap of zinc‐blende CdSe and Cd1−xZnxSe has been determined over the entire range of composition from optical transmission and reflection measurements at temperatures between 5 and 300 K. The experimental results can be expressed by the following modified empirical Varshni formula, whose parameters are functions of the composition x: Eg(x,T)=Eg(x,0)−β(x)T2/[T+γ(x)]. Eg(x,0) exhibits a nonlinear dependence on composition, according to Eg=Eg(0,0)(1−x)+Eg(1,0)xax(1−x). The parameters β(x) and γ(x) can be expressed by β(x)=β(0)(1−x)+β(1)x+bx(1−x) and γ(x)=γ(0)(1−x)+γ(1)x.