engleski

The effects of crystal size on the Raman spectra of nanophase TiO2

Raman scattering was applied as a probe for the evolution of the crystalline size and distribution of nanosized TiO2. Small physical dimenisions of TiO2 crystals lead to a shift and broadening of the first-order Raman lines through a relaxation of the q=0 selection rule and affects on the position of a low-frequency Raman (LFR) band. The details of the evolution of the 144 cm-1 Raman line shape ( frequency, broadening and asymmetry) on the size and distributions of the nanocrystals are presented. The methodologies for the size distribution were analyzed. Both the Raman results were compared with the grain size distribution obtained by high-resolution electron microscopy.

phonon confinment; Raman spectra; HREM; low-frequency Raman; TiO2

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