Polar optical-phonon scattering in three- and two-dimensional electron gases

Abstract

The concept of the polar optical momentum relaxation time for phonon energies larger than the thermal energy is applied to the analytical calculations of the electron mobility in bulk GaAs and in a two‐dimensional (2D) electron gas. The theory also accounts for nonparabolicity. For the bulk material, the analytical formula is in good agreement with experimental data even at elevated temperatures where it can be used as an extrapolation formula. The comparison with numerical simulations for the 2D gas shows that the analytical formula for the 2D case applies when intersubband scattering is unimportant. When many subbands are involved in scattering processes, the polar optical mobility can be estimated using the analytical formula for the bulk case. Hence the results provide convenient analytical equations for polar optical mobility which can be used in device simulators.