Recombination kinetics of excess carriers in semiconductor quantum wells

Abstract

A theoretical investigation of radiative and nonradiative recombination of excess carriers in a semiconductor quantum well (QW), which takes into account the exciton screening effect, is presented. The analytical formula of photoluminescence (PL) lifetime and efficiency of a QW are obtained. Calculations for the case of GaAs/AlGaAs quantum wells show that the variation of PL lifetime and efficiency with temperature is strongly related to material characteristics as well as the detailed growth techniques. When the ratio of the radiative recombination rate to the nonradiative recombination rate is less than unity, there is no characteristic temperature. In the regime of low excitation intensity, the increase of the majority carrier density is helpful to enhance the formation of the electron-hole pairs into excitons. Under higher excitations, the exciton population factor and the PL efficiency increases with increasing excitation intensity. The exciton screening effect depends, in addition to excitation intensity, upon background carrier density.