Formation and Recombination Dynamics of Charged Excitons in a GaAs Quantum Well

Abstract

We report a time-resolved photoluminescence study of negatively charged excitons (X–) in remotely doped GaAs/AlGaAs quantum wells. We measure the effects of temperature, electron density and magnetic field on the X– formation process (X + e– → X–), thereby demonstrating that it can be regarded as a classical exciton–electron scattering process. At low electron densities we find a linear dependence of the X + e– → X– formation rate on electron concentration and perpendicular magnetic field. At high electron densities, for which X– formation is very fast, the PL decay time is a direct measure of the X– intrinsic lifetime τx–. We demonstrate experimentally the dependence of τx– on the X– homogeneous linewidth.