Hot Electron Transport

In a high electric field, a population of electrons may be driven out of thermal equilibrium with the crystal lattice, hence becoming ‘hot’. In this chapter, the basic concepts of hot electron transport in semiconductors are introduced following a semiclassical approach. Scattering mechanisms pertinent to hot electron transport are described, including phonon, electron–electron and alloy scattering. The high-field phenomena of avalanche breakdown and negative differential resistance are discussed qualitatively in terms of the underlying physics and as a motivation for device applications. Techniques to solve the Boltzmann transport equation are then introduced. A low-field solution, including an introduction to the ladder method for dealing with polar optical phonon scattering, is first discussed as a foundation for the subsequent high-field solution.