Effect of doping profile on multisubband electron mobility in AlGaAs parabolic quantum well structures

We analyse the low temperature multisubband electron mobility in an AlxGa1-xAs parabolic quantum well in which the side barriers are delta doped with Si. We change the doping profile and other structure parameters to study their effect on the electron mobility mu through intersubband effects. We show that with increase in surface electron density N-s the mobility due to ionized impurity (Imp-) scattering mu(Imp) increases while due to alloy disorder (Al-) scattering mu(Al) decreases. As long as single subband is occupied, mu is governed by both Imp- and Al-scatterings. Once double subband is occupied, mu is determined by Imp-scattering only through intersubband effects. We show that increase in mu with increase in spacer width at a certain well width can be enhanced by increasing N-s. Further we show that the mobility enhances by reducing the curvature of the parabolic potential. The mobility is more when there is doping in both of the side barriers compared to single side doping. Our results of electron mobility in a parabolic quantum well can be utilized for low temperature device application. (C) 2014 Elsevier B.V. All rights reserved.