Hot-electron spectroscopy of GaAs.

We report results both experimental and theoretical on the dynamics of hot electron transport in GaAs. Total elastic and inelastic scattering rates are calculated and compared with the results of a new experimental technique "Hot Electron Spectroscopy". The magnetic field dependence of hot electron spectra has been studied. It is shown that application of a magnetic field normal to the injection direction has a dramatic effect on the spectra whereas a magnetic field applied parallel to the injection direction has no effect. The magnetic field is shown to increase the effective transit region width of the spectrometer enabling us to obtain a scattering rate for hot electrons. The experimentally determined rate gives good agreement with a theoretically determined rate considering scattering by coupled plasmon/phonon modes. Hot electron transport is of both fundamental and technological importance. Historically, the high field transport measurements of Shocklcy and Ryder t, the Gunn effect 2 and the luminescence studies d Shah and Ldtc 3 were all crumples of hot dcctrcn effects in semiconductors. However, none d this pioneering work gave direct spectroscopic information on the behavior d hot electrom in solids. Today, with ever decreasing device dimensions it is more important than ever to understand the behavior of hot dcctrcm in smaU scale structures. Infact, until recently, an understanding of hot dcctron effects in semiconductors has been limited by a lack cf experimental data with which to compare theoretical predictions. The introduction cf a new technique "Hot Electron Spectroscopy"* has changed this situation. Using this technique one may now obtain direct spectroscopic information m the dynamics of non-equilibrium carriers in semiconductors.