Three-dimensional nonequilibrium interface conditions for electron transport at band edge discontinuities

The author addresses the problem of boundary conditions for electron transport at interfaces of different material species from a fundamental microscopic point of view in order to derive self-consistent boundary conditions for various transport models and to help select a suitable model for the consideration of interface effects. A three-dimensional nonequilibrium interface condition for the Boltzmann equation at heterojunctions is set up, where the heterojunction is modeled by a band-edge discontinuity. From this interface condition, respective conditions for the moments of the distribution function are derived. Application to a selected transport model results in conditions stating continuity of quasi-Fermi level, electron temperature, and the normal component of the particle current density, and yields relations between the tangential components of the particle- and energy-flux vectors on both sides of the interface. These interface conditions enable numerical simulations of hot electron transport to be carried out at abrupt interfaces of different material species