Hot-electron transport in heavily doped GaAs

The authors report measurements on the generation and relaxation of hot electrons in GaAs. Triangular barriers of compositionally graded Al x Ga 1-x As are used in 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 they find good agreement between theory and experiment, but they note a significant discrepancy between numerical and experimental data for n=5*10 17 cm -3 .