Tunneling dynamics in QW systems investigated by femtosecond correlation spectroscopy

The tunneling dynamics of excitons and free carriers in AlGaAs/GaAS near-surface quantum well (NSQW) structures has been investigated by means of time-resolved optical techniques. The competing processes of carrier tunneling out of the quantum well and exciton formation and recombination inside the quantum well have been studied in the range of the excitation densities relevant to device applications. A consistent picture capable of fully describing the carrier and exciton-tunneling mechanisms has been obtained.