TEMPERATURE-DEPENDENT RADIATIVE RECOMBINATION OF FREE-EXCITONS IN HIGH-QUALITY GAAS HETEROSTRUCTURES

We have measured photoluminescence decay kinetics versus temperature f or high-quality MOCVD GaAs/Al0.3GaAs0.7 double heterostructures which have been thoroughly characterized at room temperature. The measured l ifetime 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 th ermal ionization of the excitons. The theory shows that the temperatur e dependence of the decay kinetics can be nearly entirely explained in terms of a temperature-independent radiative lifetime.