MODELING THE OPTICAL DIELECTRIC FUNCTION OF II-VI COMPOUND CDTE

In previous papers, a new model was proposed for the optical dielectric function of zinc blende semiconductors and was applied successfully to the alloy series AlxGa1-xAs. It was found to be more generally valid than any previous model. In this paper, it is used to obtain an analytic expression for the dielectric function of the II-VI compound CdTe at room temperature. Unlike the previous application, additional polynomial terms in the real part of the optical dielectric function are not introduced, so that the Kramers-Kronig relationship between the real and imaginary parts of the dielectric function is satisfied exactly. As demonstrated before, the model covers not only the entire photon energy range of the given spectral data, but also is valid below and somewhat above the given spectral range. This is advantageous especially when spectral data are not provided in the range of interest, or when joining two separate data causes an artificial discontinuity. The model determines the optical dielectric function in the limit as the line broadening approaches zero, which is useful in calculating the optical dielectric function at all temperatures. For demonstration, the optical dielectric function at 70 K and 600 K is calculated and presented. (C) 1995 American Institute of Physics.