The influence of crystal imperfections on the shape of exciton emission spectrum in ZnO single crystals

Abstract

A distortion of exciton emission spectrum, namely, relative decrease of free exciton band intensity with respect to that of its phonon replicas in undoped as-grown ZnO single crystals has been shown to result from enhanced reabsorption of shorter wavelength emission in the crystal due to formation of optical absorption tail. Some crystal imperfections, in all probability, dislocations decorated with shallow donors are supposed to be responsible for the effect.