Time-of-flight in lithium-compensated GaAs

Electrical properties observed in time-of-flight measurements in semi-insulating lithium-doped GaAs are characteristic of materials with dispersive transport as may be expected when potential fluctuations due to compensation and spatial disorder of impurities are present. From the experimental data we calculate the drift mobility of carriers in the samples. The Hall and drift mobilities are used as input parameters in a theoretical model that is used to estimate the magnitude of electrostatic potential fluctuations in the material due to self-compensation of lithium.