ULTRAFAST RELAXATION OF PHOTOEXCITED CARRIERS IN SEMICONDUCTOR QUANTUM WIRES - A MONTE-CARLO APPROACH

A detailed analysis of the cooling and thermalization process for phot ogenerated carriers in semiconductor quantum wires is presented. The e nergy relaxation of the nonequilibrium carrier distribution is investi gated for the ''realistic'' case of a rectangular multisubband quantum -wire structure. By means of a direct ensemble Monte Carlo simulation of both the carrier and the phonon dynamics, all the nonlinear phenome na relevant for the relaxation process, such as carrier-carrier intera ction, hot-phonon effects, and degeneracy, are investigated. The resul ts of these simulated experiments show a significant reduction of the carrier-relaxation process compared to the bulk case, which is mainly due to the reduced efficiency of carrier-carrier scattering; on the co ntrary, the role of hot-phonon effects and degeneracy seems to be not so different from that played in bulk semiconductors.