Electrical Properties ofn-Type Epitaxial GaAs at High Temperatures

Abstract

The Hall coefficient and Hall mobility have been measured in the temperature range 300-800 K on samples of $n$-type vapor-phase epitaxial GaAs from which the substrate has been removed by polishing to eliminate substrate conduction at high temperatures. The mobility varies as $T^{-1.25\mathrm{}}$ in the range 300-500 K and is compared with recent theoretical calculations. The thermal transfer of electrons from the $〈000〉$ to $〈100〉$ conduction-band minima is evident in the temperature dependence of both the mobility and the Hall coefficient, and the latter is used to derive the energy separation of these valleys as 0.38±0.05 eV using an analysis which minimises the effect of the temperature variation of the Hall scattering factor.