On the theory of absorption and luminescence spectra in amorphous semiconductors

Optical transitions in a system of randomly distributed localized electron states coupled to the phonon system are considered. A general expression for the spectral dependence of the absorption coefficient and the luminescence intensity is derived. This expression is applied to the uncorrelated case where the spectral dependences are determined by a density‐of‐states model. Various types of optical transitions within a density‐of‐states model are considered and the corresponding spectral dependences discussed. The derived spectral representation allows the direct calculation of the temperature dependent moments for the various bands.