Enhancement of binding energies and polarized emission of 0D biexcitons

The energy states of quasi zero-dimensional biexcitons are studied in epita xially grown CdS/ZnS quantum structures. Selecting a semiconductor structur e with high bulk exciton energy, comparatively small ratio in effective mas ses and strong 3D quantum confinement. an engineering of biexciton binding energies was possible towards highest values even exceeding the bulk excito n Rydberg energies. At low temperatures, the biexciton-phonon interaction i s dominated by coupling to acoustic phonons. A strong enhancement of exchan ge splitting effects is observed resulting in two linearly polarized excito n peaks. The unusual preference polarization of the biexciton emission is a ttributed to a relaxation of selection rules because of anisotropies in the confining potentials and mixing of valence band states.