Electron mobility in modulation-doped heterostructures

Abstract

A model for electron mobility in a two-dimensional electron gas confined in a triangular well was developed. All major scattering processes---i.e., deformation potential and piezoelectric acoustic, polar optical, ionized impurity, and alloy disorder---were included as well as intrasubband and intersubband scattering. The model is applied to two types of modulation-doped heterostructures, namely GaAs-GaAlAs and ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As-${\mathrm{Al}}_{0.52}$${\mathrm{In}}_{0.48}$As. In the former case phonons and remote ionized impurities ultimately limit the mobility, whereas in the latter, alloy disorder is a predominant scattering process at low temperatures. The calculated mobilities are in very good agreement with recently reported experimental characteristics for both GaAs-${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Al}}_{x}\mathrm{As}$ and ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As-${\mathrm{Al}}_{0.52}$${\mathrm{In}}_{0.48}$As modulation-doped heterostructures.