Electron mobility in modulation-doped heterostructures

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-${\mathrm{Ga}}_{1-x}{\mathrm{Al}}_x\mathrm{As}$ and ${\mathrm{In}}_{0.53}$ ${\mathrm{Ga}}_{0.47}$As-${\mathrm{Al}}_{0.52}$ ${\mathrm{In}}_{0.48}$As modulation-doped heterostructures.