Numerical studies of two-dimensional photocarrier transport in quantum wells

Abstract

Ensemble Monte Carlo simulation has been performed to study the initial spatial transport of nonequilibrium photogenerated electrons and holes in a quantum well structure. The spatial distributions have been simulated over a wide range of excitation energies and temperatures, including both the carrier - carrier and carrier - LO phonon scatterings with the help of the local density approximation. It has been found that the energy relaxation and hence the spatial transport are strongly dependent on the excitation energies, reflecting whether the relaxation channel via LO phonon emission is available or not. The spatial transport is quenched when the energy relaxation is accelerated by LO phonon emission. This excitation energy dependence of the spatial transport reduces with the increase of the carrier densities because the relative weight of the carrier - carrier scattering to the LO phonon emission changes.