Effect of doping on photoluminescence upconversion in GaAs/AlxGa1−xAs heterostructures

We report on the effect of doping on the efficiency of the upconverted photoluminescence (UPL) from GaAs/AlGaAs heterostructures. The UPL intensity is enhanced when the AlGaAs layer is remotely doped with holes. It indicates that the rate-limiting process for the upconversion is the excitation of holes. Our result shows that one has to be careful in interpreting the excitation power dependence of the UPL intensity because dissimilar excitation efficiencies for electrons and holes and a possible background doping of the samples can significantly modify the excitation power dependence.