Analysis of Polar Optical Scattering of Electrons in GaAs

The theory of the scattering of electrons by longitudinal optical phonons in III-V compounds is reconsidered, in the nondegenerate limit, assuming a spherical conduction band. The off-equilibrium part of the distribution function and the Hall-mobility-temperature function are obtained with a numerical resolution of the Boltzmann equation, up to a precision of a few 10−4. The results are compared with previous work due to Sondheimer and Howarth, and Ehrenreich. Application of the theoretical results to high-purity epitaxially grown GaAs layers is in good agreement around 300°K, but there is a strong discrepancy at higher temperatures. It is suggested that such a discrepancy could be explained by further refinements of the present theory (temperature dependence of the dielectric constant, two-phonon process).