Capture of carriers excited by interband and intersubband absorption in GaAs/AlAs/AlGaAs double-barrier quantum wells

We report on the carrier dynamics in n-type double-barrier quantum well structures in an electric field. Both the intersubband and interband photocurrents, excited by long-wavelength (4μm) and short-wavelength (0.5μm) radiation, respectively, show a photovoltaic asymmetry with respect to the applied field. This asymmetry arises from an internal field due to an asymmetric dopant distribution with respect to the well centers. Time-dependent photoluminescence measurements allow us to determine the field dependence of the electron and hole capture times.