Relaxation of a kinetic hole due to carrier-carrier scattering in multisubband single-quantum-well semiconductors

We describe a theoretical model for carrier-carrier scattering in an inverted semiconductor quantum well structure using a multisubband diagram. The model includes all possible nonvanishing interaction terms within the static screening approximation, and it enables one to calculate accurately the temporal evolution of the carrier densities and the gain following a perturbation by a short optical pulse. We present a theoretical formalism and detailed numerical calculations. The addition of more than one subband in each band as well as the use of all exchange terms yields several results. First, the degree of gain saturation is reduced while, at the same time, the recovery is faster as scattering events among different subbands take place. Also, carrier transfer between subbands is observed which modifies the overall carrier dynamics.