Raman spectral analysis of TiO2 thin films doped with rare-earth samarium

TiO2 thin films doped with rare-earth samarium were prepared on a quartz plate by the sol-gel/spin-coating technique. The samples were annealed at 700 degrees C to 1100 degrees C, and the Raman spectra of the samples were obtained. Analyses of Raman spectra show that samarium doping can inhibit the anatase-rutile phase transition. Samarium doping can refine grains of TiO2 thin films and increase the internal stress, thereby preventing lattice vibration. Nanocrystalline TiO2 thin films obviously show the phonon confinement effect, i.e., the blueshift of characteristic Raman peak and full width at half-height increase, and the peak shapes asymmetrically broaden with a decrease in the grain sizes of the samples. (C) 2012 Optical Society of America