TEMPERATURE-DEPENDENCE OF OPTICAL-TRANSITIONS BETWEEN ELECTRONIC-ENERGY LEVELS IN SEMICONDUCTORS

We propose a model to describe temperature-dependent electronic transi tions using an effective electron-ion interaction. We present a nonper turbative calculation of the temperature dependence of the forbidden e nergy gap of CdTe crystals. The results are compared with similar calc ulations using the statistical-function method and both give good agre ement with experimental data. It is also demonstrated that the thermal expansion of the lattice plays a minor role for the temperature varia tion of the electronic energy levels.