Two-dimensional electron transport in semiconductor layers. I. Phonon scattering

Abstract

The basic theory of lattice scattering for electrons in a semiconductor heterolayer, and resulting transport properties in two dimensions parallel to the layer plane, are investigated, specifically for polar semiconductors such as gallium arsenide. Because of polar coupling of the electron states in this system to the lattice modes, the scattering functions are more complicated than is found for the ordinary Bloch states in homogeneous semiconductors. This is true of acoustic modes, as well as optical modes, in that piezoelectric coupling may not be neglected. The ohmic mobility at moderately low temperatures is calculated, and displayed for 150 K. It is a strongly increasing function of the layer thickness. An approximation scheme for higher temperatures is developed. More generally, and particularly for hot electrons, computer calculation of transport properties is necessary. Use of pretabulated and stored functions may be required for this. Monte Carlo simulation will require special procedures, because of the large range of values of the scattering rates and to accommodate the infinities in piezoelectric-coupled scattering. These are developed here. © 1981.