Hot Electron Emission in Semiconductors

摘要

The spectrum of the simulated far infrared emission from p-Germanium in crossed electric and magnetic fields is studied by means of a tunable narrow-band GaAs-detector. A multimode spectrum is observed from polished high parallel samples. The mode spectrum is quantitatively explained in terms of internal waveguide-like modes. With the help of an external resonator the number of modes was drastically reduced. The external resonator has a confocal configuration. For the first time a single mode operation is demonstrated. The problem of the electron distribution in crossed electric and quantizing magnetic fields is treated for free electrons in a parabolic band. The master equation for the diagonal elements of the density matrix is solved including the kz-dependence of the electron distribution. It is shown that population inversion between Landau levels can be achieved if scattering by optical phonons and a quasi-elastic scattering process are taken into account.