2-PHOTON ABSORPTION OF BIEXCITONS IN ZNS-BASED QUANTUM-WELLS

Two-photon absorption processes of biexcitons in ZnS-based quantum-wel l structures have been studied by means of photoluminescence excitatio n spectroscopy. The peak position of two-pho ton absorption of biexcit ons was dependent on the detected energy position in the photoluminesc ence excitation measurement. The energy difference between the one-pho ton exciton resonance and the two-photon biexciton resonance increased as the detected energy position was moved towards the lower-energy si de of the biexciton luminescence. This result indicated the biexciton localization and the resultant increase in the biexciton binding energ y. (C) 1998 Elsevier Science B.V. All rights reserved.