Temperature-dependent radiative recombination of free excitons in high-quality GaAs heterostructures

We have measured photoluminescence decay kinetics versus temperature for high-quality MOCVD GaAs/Al0.3GaAs0.7 double heterostructures which have been thoroughly characterized at room temperature. The measured lifetime is in good agreement with the lifetime obtained from a kinetic model of interacting free carriers and excitons. This theory explains the evolution from exponential decay at very low temperatures to more nonexponential bimolecular decay at higher temperature in terms of thermal ionization of the excitons. The theory shows that the temperature dependence of the decay kinetics can be nearly entirely in terms of a temperature-independent radiative lifetime. © 1994.