Tunneling dynamics of photogenerated carriers in semiconduc- tor superlattices

The tunneling dynamics of photogenerated carriers in GaAs-Al0.29{Ga}0.71$As multiple-quantum-well structures are studied using picosecond spectroscopy with the electric field perpendicular to the well layers. Drastic changes, such as an increase in the photocurrent, a decrease in the exciton luminescence, and a change in the exciton lifetime, take place simultaneously for electric fields of {~}5.0×{}10³ V/cm. These changes are ascribed to the onset of exciton dissociation and the electron tunneling through the Al0.29{Ga}0.71$As barrier layers. The electron tunneling rate is determined to be 1/(430 ps) and is compared with calculations.