Drude absorption and electron localization in GaAs/AlGaAs superlattices

摘要

We have investigated the electron conduction in semiconductor superlattices (SL) by measuring free carrier absorption by far-infrared (FIR) spectroscopy. It is found that the momentum relaxation time, #tau#, is quite anisotropic; #tau# in the SL direction (growth direction), #tau#_(SL), being approximately shorter by a factor of two than that for the in-plane direction, #tau#_(||). Furthermore, suppression of the long-range conductivity in the SL direction has been observed and attributed to the localization due to potential disorder.