INFLUENCE OF II-VI NANOCRYSTAL SHAPES ON OPTICAL-PROPERTIES

A tight-binding model is used to investigate shape effects on the elec tronic structure and optical properties of nanocrystals. We have calcu lated the absorption spectra of ZnS and CdSe crystallites with differe nt morphologies: spherical clusters, facetted nanocrystals and ellipti c crystallites. We have performed a complete comparison of the energie s and absorption bands as a function of the morphological changes. We show that the first transition energies are only slightly affected by shape effects. On the other hand, the exact shape of nanocrystals lead s to strong modifications of the features of the optical spectra. (C) 1998 Elsevier Science B.V. All rights reserved.