Temperature-dependent electron-lattice thermalization in GaAs
Résumé
Thermalization of hot electron with the lattice is precisely investigated in bulk GaAs in the temperature range 50–300 K using a high-sensitivity two-color femtosecond absorption saturation technique. The results show that for lattice temperatures larger than 100 K, the photoexcited electron gas eventually thermalizes with the lattice with a characteristic time close to the LO phonon lifetime as a consequence of the nonequilibrium hot-phonon effect. For lower temperatures, the electron-lattice thermalization time is found to be longer than the LO phonon lifetime in agreement with numerical simulations of the coupled carrier-LO phonon dynamics.