Electrical properties of low-compensation GaAs

Recently we have reproducibly grown vapor-phase epitaxial GaAs, with less than 10% compensation, in an As${\mathrm{Cl}}_3$-Ga-${\mathrm{H}}_2$ reactor. The low-temperature electrical properties of such samples are quite interesting, with neutral-impurity scattering and screening being much more important than usual. The Hall mobility is typically above ${10}^5$ ${\mathrm{cm}}^2$/V sec at 5 K and has two maxima as a function of temperature, the usual one near 50 K and another near 9 K. The latter phenomenon has not been observed before, to our knowledge. The mobility and carrier concentration temperature dependences for a low-compensation sample and a normal-compensation sample are theoretically fitted to determine the donor and acceptor concentrations. The low-compensation sample has $\frac{N_A}{N_D}=0.06\mathrm{}\pm 0.03$.