Interpretation of asymmetric band shapes in terms of bound exciton complexes

Abstract

The cathodoluminescence edge emission of zinc telluride has been found to contain a most unusual broad, asymmetric emission band which, at 77 K, occurs at 526.2 nm (2.356 eV). The observed properties of this band as a function of temperature and excitation intensity cannot be explained in terms of conventional luminescence models. It is shown that a model for this centre based on the binding of an exciton to a dipolar field resulting from an ionized donor-acceptor pair can account for the anomalous behaviour of the emission, under the assumption that appreciable lattice relaxation occurs in the vicinity of the bound exciton complex.