Electrical Properties ofn-Type Gallium Arsenide

As part of a general investigation into the properties of gallium arsenide, the Hall coefficient and resistivity of three pure samples have been measured from 300 to 2°K. The highest mobility measured at 300°K was 7200 ${\mathrm{cm}}^2$/V-sec increasing to 22 000 ${\mathrm{cm}}^2$/V-sec at 72°K, the mobility temperature curve following the theory of Ehrenreich very closely. At helium temperatures impurity conduction was observed with the resistivity $\rho \propto \exp (-\frac{{\epsilon }_1}{\mathrm{kT}})$ and ${\epsilon }_1$ varying from 9.8×${10}^{-5\mathrm{}}$ eV to 5.8×${10}^{-4\mathrm{}}$ eV. A discussion of these results is given in terms of the theory of Miller and Abrahams and Twose.