Room-temperature photoluminescence times in a GaAs/Al<i>x</i>Ga1−<i>x</i>As molecular beam epitaxy multiple quantum well structure

Abstract

Time-resolved photoluminescence measurements at room temperature of the n=1 heavy hole transition in a GaAs/AlxGa1−xAs multiple quantum well structure reveal a single-exponential decay with τ≊1 ns over a wide range of excitation densities. Time-integrated photoluminescence increases as the square of excitation energy density. These data indicate that the observed decay rate is due to nonradiative recombination. Free carriers, not excitons, govern radiative recombination in this sample.