Abstract

The relaxation of photo-excited hot carriers in GaAs is difficult to measure because of the time scale involved is so short. Generally the hot electrons relax at low lattice temperatures in three stages. First, hot carriers thermalize through electron-electron and LO phonon scattering and fall to an energy range where the electron population can be described by Fermi distribution (electron temperature, T_e, greater than lattice temperature). Then this quasi-equilibrium distribution cools through the emission of LO phonons by the electrons in the high energy tail. After the carrier temperature is below about 30K, acoustic phonon emission slowly cools the distribution to the lattice temperature. Our experiment measures the average thermalization rate during the first stage of this process.

© 1986 Optical Society of America