OBSERVATION OF 3 ELECTRONIC-TRANSITIONS IN CD(S,SE) NANOCRYSTALS BY MODULATION SPECTROSCOPY

We report absorption and electromodulated transmission spectra for a s eries of CdS0.44Se0.56 nanoparticle/glass composites in which the aver age particle radius was varied from less than 2 nm to more than 6 nm b y thermal treatment. We observe at least three distinct modulation pea ks which shift with particle size. Two of these peaks have been previo usly identified but we believe that the third is a new observation in electromodulation spectroscopy. We discuss the size-dependence of the energy, spectral shape, and magnitude of these modulation peaks.