Ensemble Monte Carlo simulations of femtosecond thermalization of lowhyphen;energy photoexcited electrons in GaAs quantum wells

摘要

We present results of ensemble Monte Carlo simulations of the roomhyphen;temperature relaxation of nonthermal photoexcited electrons in GaAs quantumhyphen;well structures. Electrons are excited at a mean energy of 20 meV above the band edge, similar to the experiments of Knoxetal. lsqb;Phys. Rev. Lett.56, 1191 (1986)rsqb; and Oudaretal. lsqb;Phys. Rev. Lett.55, 2075 (1985)rsqb;. Since this energy is less than the opticalhyphen;phonon emission threshold, energy relaxation occurs primarily via carrierhyphen;carrier scatterings. We find that the excited electrons thermalize with the background electrons within 200 fs, in agreement with experiment.