Carrier-carrier scattering and optical dephasing in highly excited semiconductors

A quantitative analysis of carrier-carrier scattering and optical dephasing in semiconductors is presented and results are given for quasiequilibrium situations and for the relaxation of a kinetic hole in a quasithermal carrier distribution. The calculations involve direct numerical integration of the Boltzmann equation for carrier-carrier scattering in the Born approximation. The screening of the Coulomb interaction is treated consistently in the fully dynamical random-phase approximation. Carrier relaxation rates are extracted from the Boltzmann-equation solution and a quantitative test of the relaxation-time approximation for situations near thermal quasiequilibrium is performed. The parametric dependence of carrier-collision rates and dephasing on plasma density, temperature, and electron and hole masses is discussed and analyzed in terms of phase-space blocking and screening.