Enhancement of Multisubband Electron Mobility in Barrier Delta-Doped Asymmetric GaAs/AlGaAs Double Quantum Well Structure

Abstract

ABSTRACTWe analyse the effect of asymmetry in the structure parameters on low-temperature multisubband electron mobility μ in a barrier delta-doped GaAs/AlGaAs double quantum well structure. We obtain the subband energy levels and wave functions through self-consistent solution of Schrodinger and Poisson's equations. We show that μ is enhanced through asymmetry in well widths and spacer widths as a function of doping concentration, mediated by intersubband effects. We analyse the interplay of different scattering mechanisms on μ and show that the nonlinear enhancement of μ arises due to interface roughness (ir-) scattering even though the mobility is mostly limited by ionized impurity (imp-) scattering. We further show that the range of μ up to which the ir-scattering dominates depends on the occupation of subbands. Our results can be utilized for low-temperature devices.