Electron mobility in one (two)-side modulation-doped GaAs/AlxGa1-xAs asymmetric quantum wells

We have calculated the electron mobility in one (two)-side modulation-doped GaAs/AlxGa1-xAs asymmetric quantum wells. Coupled Schrodinger and Poisson equations were solved through the extended Fang-Howard variational method b y considering the effective mass approximation, finite well barriers, the e xchange-correlation correction to the effective potential and electrons in the quantum limit. The results were used to determine the electron mobility where only the relevant scattering processes, namely acoustic-phonon, ioni zed impurity, alloy disorder and interface roughness were considered. The p artials and total mobility dependences on temperature were found and from t he acoustic-phonon scattering contribution we have determined the temperatu re coefficient a. It is shown that the ionized impurity scattering is the d ominant mechanism and that alloy disorder scattering overcomes acoustic-pho non scattering at very low temperatures. The ionized impurity and total mob ilities were also related to the spacer width and the two-dimensional elect ron gas density. We have also considered the inclusion of a second modulati on-doping spike on the reverse side of the quantum well and its effect on m obility has been discussed.