Effective radiative recombination coefficient of p-AlGaAs for varying aluminium concentrations

The effective radiative recombination coefficient of p-AlGaAs was experimentally determined for different sample geometries and compositions. Double-heterostructures with varying active layer thicknesses and aluminium concentrations between 0.08 and 0.23 were grown using metalorganic vapor phase epitaxy. Combining injection-dependent and time-resolved photoluminescence measurements allowed to compute the effective radiative efficiency as a function of excess carrier density and to extract the effective radiative recombination coefficient. For increasing active layer thickness and for increasing aluminium content the effective radiative recombination coefficient decreases in agreement with numerical modelling. Optical interference effects, in particular for thin samples, make the results susceptible to small variations in sample thickness and additional layers underneath the double-heterostructure. The extracted non-radiative lifetimes imply the existence of three different defects, independent of composition and thickness, that are dominant in different carrier injection regimes. A sensitivity analysis of the presented method revealed that the low-injection carrier lifetime and the doping concentration are the two most critical input parameters whose combined uncertainties amplify the error on the obtained effective radiative recombination coefficient.