Femtosecond studies of real-space transfer in AlGaAs/GaAs heterostructures

Abstract

The vertical transport of optically injected carriers in the thin AlGaAs layer of GaAs/AlGaAs single heterostructures is investigated by means of femtosecond time-resolved luminescence (“population-mixing” technique). Depending on the AlGaAs thickness, lifetimes of the combined electron-hole populations of 5–11 ps are observed. We attribute the effect mainly to separation of electrons and holes by the built-in electric field, which causes real-space transfer of holes, since the electrons are “trapped” in the potential minimum of the AlGaAs layer.