PARAMETERIZATION OF THE OPTICAL FUNCTIONS OF AMORPHOUS MATERIALS IN THE INTERBAND REGION

A parameterization of the optical functions of amorphous semiconductor s and insulators is presented in which the imaginary part of the diele ctric function epsilon(2) is determined by multiplying the Tauc joint density of states by the epsilon(2) Obtained from the Lorentz oscillat or model. The real part of the dielectric function epsilon(1) is calcu lated from epsilon(2) using Kramers-Kronig integration. The parameters of this model are fit to n and k data for amorphous Si (2 data sets), SiO, As2S3, and Si3N4 Comparative fits are made with a similar parame terization presented earlier by Forouhi and Bloomer [Phys. Rev. B 34, 7018 (1986)]. In all cases, the new parameterization fits the data bet ter. (C) 1996 American Institute of Physics.