Carrier trapping in room-temperature, time-resolved photoluminescence of a GaAs/AlxGa1−xAs multiple quantum well structure grown by metalorganic chemical vapor deposition

Abstract

The time decay of the room-temperature photoluminescence from the n=1 transition in a multiple quantum well structure grown by metalorganic chemical vapor deposition is observed to depend strongly on excitation energy density. For low excitation (0.2 μJ/cm2) an exponential 3-ns decay is observed, while for high excitation (120 μJ/cm2) the decay lengthens to 45 ns. In the case of higher excitation, the photoluminescence decay rate is observed to increase after excitation and initial decay. The excitation energy dependence of the initial decay can be explained by saturation of carrier traps, and the later speedup of photoluminescence decay can be explained by the release of carriers from the traps and subsequent refilling. Time-integrated photoluminescence data qualitatively support the trapping interpretation. This is the first report, to the best of our knowledge, of time-resolved photoluminescence in a metalorganic chemical vapor deposition grown GaAs/AlxGa1−x As quantum well structure.