On the determination of carrier mobility in compensated GaAs

The applicability of the Brooks-Herring and Conwell-Weisskopf formulas in calculations of the carrier mobility associated with scattering by ionized impurities is examined usingn-type GaAs as an example. The Brooks-Herring approximation is shown to be inapplicable at large compensation ratios, where the Conwell-Weisskopf formula is more accurate. The applicability limits of the two formulas are established for calculations of carrier mobility from dopant concentration and compensation ratio and for calculations of the concentration of ionized centers (compensation ratio) from carrier concentration and mobility. The predicted applicability limits are consistent with experimental data.