Investigation of carrier transport in graded gap superlattices by time correlated single photon counting

摘要

Carrier transport in asymmetric superlattice structures is investigated by a photoluminescence technique based on single photon counting. Hole drift times as short as 40 ps have been measured at room temperature in a compositionally graded AlGaAs superlattice with a 540 Aring; period. Our studies also reveal the complex dynamics of the carriers in these structures and particularly the role of quasihyphen;electric fields, photoinduced fields, and traps. Excellent agreement with previous measurements of charge transport optical nonlinearities based on electrohyphen;optic sampling is found.