INVESTIGATIONS OF THE EMISSION PROPERTIES OF SINGLE CDS-NANOCRYSTALLITES

Semiconductor nanocrystallites (NCs) with a radius in the range of the bulk exciton radius exhibit a strong quantum size effect. We investig ated CdS-NCs, that were spin coated on a glass cover slip, with a low temperature confocal microscope. At low coverage we could image the fl uorescence light from single NCs. The typical emission spectra of sing le NCs show four peaks. Besides the main peak related to near bandgap recombination, up to two LO-phonon satellites and one blue shifted pea k were observed. It could be shown that the absorption can be polariza tion dependent. From the images as well as from the intensity autocorr elation function it could be concluded that the fluorescence emission of single NCs is interrupted by dark periods. In addition, spectral sh ifts in the dispersed fluorescence emission could be observed.