Temperature Dependence of Exciton Lifetimes in GaAs/AlGaAs Quantum Well Structures

The photoluminescence decay times in GaAs/AlGaAs single quantum well structures with layer thickness between 20 Å and 80 Å have been investigated in the temperature range from 4 K up to room temperature. It is shown that the increase in the PL decay time usually ascribed to radiative free-excitons recombination is present even in conditions where other mechanisms such as recombination of localized excitons and free carriers, exciton ionization and thermal activation of nonradiative processes are effective.