Field-induced lifetime enhancement and ionization of excitons in GaAs/AlGaAs quantum wells

Abstract Picosecond and nanosecond luminescence studies of GaAs/AlGaAs quantum wells exposed to electric fields perpendicular to the layers are reported. The drastic red-shift of the photoluminescence with the electric field strength is accompanied by a strong increase of the electron-hole recombination lifetime. These features are most dominant for the wider wells due to the stronger polarization of the confined electron-hole pairs. Our observations are consistent with the model of the Quantum-Confined Stark Effect. In contrast, for high fields in the regime of ∼100 kV/cm field ionization limits the confinement of electrons and holes and leads to a strong decrease of the photoluminescence yield and lifetime with increasing field strength.