Injected-hot-electron transport in GaAs

The new experimental technique of hot-electron spectroscopy has been used, for the first time, to observe electrons in extreme nonequilibrium. When the transit-region width is comparable to the calculated hot-electron mean free path, two peaks are observed in the measured spectrum. The high- energy peak corresponds to quasiballistic electrons suffering few, if any, collisions in the transit region. The low-energy peak is due to excitation of the Fermi sea by the injected hot electrons. (Author)