Phonon-assisted exciton formation and relaxation: Bulk and two-dimensional systems

A microscopic analysis of exciton formation and relaxation in photoexcited quantum wells is presented. The theoretical approach is based on a Monte Carlo simulation of the coupled free-carrier and exciton dynamics and includes various mechanisms contributing to the formation of excitons and to their subsequent energy relaxation. Our investigation clarifies the effects of the exciton relaxation due to AC-phonon scattering in the building up of excitonic luminescence in time-resolved experiments. The role of carrier confinement is discussed for wells of different width.