The Boltzmann equation at low external electric field with dominant polar-optical-phonon scattering is accurately solved for temperatures above 77 K. Electron transport properties that include intersubband and intrasubband transitions for the two-dimensional electron gas in ${\mathrm{Al}}_{\mathrm{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As-GaAs heterojunctions are obtained numerically.

• Received 23 December 1986

DOI:https://doi.org/10.1103/PhysRevB.36.2757