High-Temperature Transport Properties of n-Type GaAs

Electrical resistivity and Hall coefficient were measured at high temperatures (300°∼900°K) for the epitaxial n-GaAs of carrier concentrations ranging from 10 14 to 10 17 cm -3 . Analysis of the Hall data for the low-concentration samples reveals the presence of a very large amount (10 19 ∼10 20 cm -3 ) of deep centers (1.2∼1.3 eV from the conduction band bottom) and a small amount (10 14 ∼10 15 cm -3 ) of less deep centers (∼0.4 eV). These are considered to be donor-like or electron trap centers. Energy difference between the (000) and (100) valleys at 0°K and its temperature coefficient were deduced to be ∼0.4 eV and 2∼3×10 -5 eV/°K from the Hall data for the high-concentration samples. Hall mobility due to polar mode and two-phonon resonant scatterings was calculated based on a relaxation time approximation. Agreement with the highest mobility data was satisfactory.