QUASI-HOLE LIFETIMES IN ELECTRON GASES AND ELECTRON-HOLE PLASMAS IN SEMICONDUCTOR QUANTUM-WELLS

The lifetime of a final-state quasihole (i.e., an empty state under the Fermi level created, for example, by interband optical transitions) due to inelastic-scattering processes is calculated as a function of the quasihole energy in n-type and p-type modulation-doped quantum wells as well as in electron-hole plasmas in undoped quantum wells. Carrier-carrier scattering and carrier-longitudinal-optical-phonon interactions are considered for the energy-relaxation processes. For carrier-carrier scattering, quasiholes are found to decay through single-particle excitations without plasmon emission at zero temperature. The dependences of the scattering lifetimes on the well width, carrier density, in-plane effective carrier mass, and temperature are studied. The effects of static and dynamic dielectric screening are compared. The relevance of these results to recent luminescence data in modulation-doped quantum wells and to recent thermalization data in hot plasmas in undoped quantum wells is discussed.