SIZE DEPENDENCE OF ACOUSTIC AND OPTICAL VIBRATIONAL-MODES OF CDSE NANOCRYSTALS IN GLASSES

The size dependence of resonant Raman scattering from acoustic and opt ical vibrational modes in CdSe nanocrystals (size less than 10 nm) emb edded in a glassy matrix has been investigated. In the low-frequency R aman scattering range (< 100 cm(-1)) a fine structure due to the confi nement of acoustic modes is observed. The Raman line corresponding to the interaction with the optical modes (new 210 cm(-1)) shifts and wid ens with a decreasing of the particle size. These experimental results can be described by a single model based on the size dependence of th e eigenvibration modes of spherical particles in a matrix.