Low frequency Raman scattering of CdS nanocrystallites embedded in silicate glasses

Small size CdS crystal doped silica glasses were prepared by sol-gel process. The results showed that the CdS microcrystal sizes can be calculated from the peaks in their low frequency inelastic Raman scattering spectra (LOFIRS). Two types of the vibrational modes were discriminated by the polarized spectra. The second-order Raman scattering peaks were assigned from the exprimental results. The results of average paticle sizes from LOFIRS can correspond to those from TEM. The blue shift in the optical absorption of the obtained glasses was closely related with the size of CdS microcrystallites. The expriment verified that there was a good inverse proportion relationship between the energy of absorption edges and the square of the size of CdS nanocrystallites.