Electric field induced enhancement of low temperature electron mobility in coupled InGaAs/InAlAs double quantum well structures

Abstract

We analyse the effect of uniform electric field on the low temperature multisubband electron mobility in an InGaAs/InAlAs double quantum well structure in which the side barriers are delta-doped with layers of Si. The electric field, which is perpendicular to the interface plane of the structure, alters the subband energy levels and wave functions which in turn leads to a change in the subband mobility. We consider ionized-impurity scattering, alloy disorder scattering and interface roughness scattering and analyse the changes in them due to the applied electric field mediated by the intersubband interactions. We show that application of the field transforms a system from double subband occupancy to single subband occupancy thereby suppressing the intersubband interaction which in turn enhances the mobility. We also change the well width to study its effect on mobility as a function of the applied electric field, which yields interesting results.