Ionized-impurity scattering of electrons in Si-doped GaAs/AlGaAs quantum wells in low and high electric fields

Abstract

The first measurements of low- and high-field transport properties of electrons in doped quantum wells are reported. We find that ionized-impurity scattering of electrons in quasi-two-dimensional systems is generally enhanced compared to that in similarly doped bulk material. This enhancement is evident not only at low electric fields, but continues to high fields, resulting in lower peak velocities. By delta-doping (rather than uniformly doping) the quantum wells, the low-field mobility is further reduced; at electric fields between 2 and 4 kV/cm, however, the differential mobility of the δ-doped quantum wells increases dramatically, also leading to higher peak velocities.