Consequences of the spatial localization on the exciton recombination dynamics in InGaP/GaAs heterostructures

GaAs/InxGa1−xP quantum wells, with x=0.541 and 0.427, have been investigated by continuous wave and time resolved photoluminescence. Spatial localization of excitons due to alloy compositional defects seem to be responsible of the observed phenomenology: non-exponential decay behavior at long times and slow decrease of the effective recombination time by increasing temperature. A two-class exciton kinetic model, based on a mobility edge varying with the temperature explain the experimental results.