Hot-electron transport in heavily doped GaAs

We report measurements on the generation and relaxation of hot electrons in GaAs. Triangular barriers of compositionally graded AI, Gal. As are used to inject hot electrons into heavily doped GaAs. The effect of the width and doping level of the GaAs transit region on the resulting hot-electron spectra is described. Magnetic-field measurements are presented which confirm the non-equilibrium nature of transport in narrow transit regions. A detailed consideration of scattering in heavily doped GaAs is given together with Monte-Carlo simulations of hot-electron spectra. For samples doped to n = 10(18) cm(-3) we find good agreement between theory and experiment, but we note a significant discrepancy between numerical and experimental data for n=5 x 10(17) cm(3).