Ionized-impurity scattering of quasi-two-dimensional quantum-confined carriers

Hall-effect measurements of electron mobility in anti-modulation-doped GaAs/AlGaAs quantum wells indicate that the ionized-impurity scattering of a quasi-two-dimensional electron gas immersed in the identical concentration of ionized impurities is greater than that of a bulk electron gas of the same density. This enhancement results from an increase of the overlap of the electronic wave function with the impurities, a decrease in screening, and an increase in large-angle scattering. The enhanced scattering rate may be further increased by confining the dopant ions to a deltalike doping profile in the center of the well. © 1991 The American Physical Society.