MICROSCOPIC THEORY FOR THE OPTICAL-PROPERTIES OF COULOMB-CORRELATED SEMICONDUCTORS

A nonequilibrium Green's functions approach is presented for the consi stent computation of semiconductor quantum well optical spectra includ ing strong Coulomb correlations within the coupled photon and carrier system. Bethe-Salpeter-like equations are given for the optical respon se and recombination rates in the excited medium. Band structure; quan tum confinement, many-body and cavity resonator effects are included i n the microscopic approach. The theory is applied to the description o f absorption/gain, luminescence, single and two-beam photoluminescence excitation spectroscopy for arbitrary temperatures and carrier densit ies. Numerical results, showing good agreement with recent experiments are presented for III-V and II-VI materials, from the linear regime, characterized by excitonic effects to the high density case in which a strongly interacting electron-hole plasma is proposed as the dominant mechanism.