New Concept for the Reduction of Impurity Scattering in Remotely Doped GaAs Quantum Wells

We present a new concept to reduce impurity scattering in remotely doped GaAs single quantum wells by using heavy-mass X electrons in barriers formed by short-period AlAs/GaAs superlattices to smooth the potential fluctuations of the ionized Si dopants. Electron mobilities as high as $120{\mathrm{m}}^2/\mathrm{V}\mathrm{s}$ and electron densities up to $1.5\times {10}^{16}{\mathrm{m}}^{-2\mathrm{}}$ are obtained in 10 nm GaAs single quantum wells in the one-subband conductivity mode without any parallel conductance. In addition to magnetotransport we present voltage dependent capacitance and photoluminescence measurements as well as self-consistent calculations to demonstrate the applicability of our concept.