Time-resolved photoluminescence spectroscopy of resonant tunneling in a GaAs-AlAs triple-barrier structure

Transport of electrons and holes through an asymmetric GaAs-AlAs triple-barrier structure is investigated using time-resolved photoluminescence spectroscopy. Carriers are excited in the GaAs contact regions of the diode only, by choosing the excitation energy below the absorption edge of the quantum-well states. The intensity, half width, and temporal development of the photoluminescence signal of the quantum-well ground-state transitions are investigated by sweeping the applied bias through the tunneling resonances. Resonant tunneling of photocreated electrons is found to occur on a time scale shorter than about 50 ps, whereas resonant transfer of holes takes about 200 ps. Nonresonant tunneling times of both types of carriers, however, are on the order of 1 ns.