Monte Carlo Studies of Hot Electrons

Through the most recent technological advances, it has been possible to get into the subpicosecond and submicron regimes, where hot electron effects are very important. The purpose of this paper is to show how the Monte Carlo technique can be successfully applied to the study of ultrafast phenomena in semiconductors. Two main topics will be dealt with: (1) the energy relaxation of photoexcited electrons in bulk GaAs and GaAs-AlGaAs quantum wells. The dynamical evolution of the polar optical phonon distribution is followed in the simulation. It is found that the presence of hot-phonons greatly reduces the cooling rate of the photo-excited electrons, in qualitative agreement with available experimental results. (2) The energy and momentum losses of hot electrons injected into a doped region, as found for example in the planar doped barrier (PDB) and in the tunneling hot electron transfer amplifier (THETA) devices. The interaction between the injected electrons and the background of cold carriers is shown to be a very effective channel of dissipation.