ENERGY-LOSS RATE OF HOT-ELECTRONS IN A SEMICONDUCTOR - THE ROLE OF ANHARMONIC INTERACTIONS

The hot-electron energy loss rate (ELR) is studied by using the nonequilibrium Green's function approach. The effect due to the anharmonic interaction is considered. As a result, hot electrons lose their energy primarily by creating pairs of acoustic phonons via LO phonons. When acoustic phonons are kept at the lattice temperature, the nonequilibrium distribution for LO phonons is derived by imposing the steady state condition. We show that our result is able to account for the dramatic enhancement of the hot-electron ELR observed in GaAs/GaAlAs semiconductors at low temperatures.