DEPHASING OF ACCEPTOR-BOUND EXCITONS IN II-VI SEMICONDUCTORS

Degenerate four-wave-mixing experiments (DFWM) at the neutral acceptor bound exciton complex in CdS and ZnSe are reported. ps- as well as fs-spectroscopy are carried out to investigate the dephasing processes at this complex. The results are discussed concerning scattering of free excitons, phonons, and interactions with impurity centers. Higher orders of diffraction in the DFWM process are modeled within the density matrix equations for noninteracting two-level systems including propagation effects. From nonlinear quantum beat spectroscopy the binding energies of the acceptor bound biexciton in CdS and ZnSe are estimated.