The properties of ZnO photoluminescence at and above room temperature

Abstract

A study of the photoluminescence characteristics of a ZnO single crystal at the temperature range 173-823 K is presented. The analysis employed the electron-phonon interaction model as well as the radiative recombination rate model. Both studies indicate that at ∼700 K the photoluminescence character undergoes a transition from being a free exciton emission to a band gap recombination, implying a breakup of excitons into free carriers is occurring. The transition temperature corresponds to ∼60 meV, which is consistent with the binding energy of the free exciton in ZnO. © 2007 American Institute of Physics.