Improvement of electron mobility mediated by interface roughness scattering in pseudomorphic GaAs/In0.15Ga0.85As asymmetric double quantum well structure

Abstract

We analyse low temperature multisubband electron mobility mediated by interface roughness (ir-) scattering i.e., µirs as a function of electric field F in a pseudomorphic modulation δ-doped GaAs/In0.15Ga0.85As asymmetry-double-quantum-well (ADQW) structure. The asymmetry is obtained by considering different (I) well widths (w1 = 100 Å and w2 = 150 Å) and (II) doping concentrations (Nd1 = 1.0 × 1018 cm−3 and Nd2 = 1.5 × 1018 cm−3). We adopt random phase approximation and calculated µirs by considering screened ir-scattering potential. The cusp like behaviour of Fermi Energy levels at resonance field Fr makes µirs non-monotonic through intersubband interaction. We show that there is an enhancement of µirs and shifting of the resonance position with increasing central barrier width b in both cases. However, in case I, the increase in Nd enhances µirs but Fr doesn’t change. Whereas, in case II, as w increases, not only µirs but also Fr changes. The effect of the structure parameters on µirs can be utilized to improve the surface roughness effect in new emerging opto-electronic devices.