SIZE-SELECTIVE RESONANT RAMAN-SCATTERING IN CDS DOPED GLASSES

The size and excitation dependence of resonant low-frequency Raman sca ttering in CdS nanocrystals (radii less than 10 nm) embedded in a glas sy matrix have been investigated. We report a size-selective excitatio n for excitations inside the absorption features. The Raman spectra ex hibit a different behavior when the excitation is below the absorption band. This behavior is shown to depend on the fabrication process of the samples and is assigned to a resonance on surface defects.