Sol-gel derived Cd- and La-modified PbTiO3 thin films

Cadmium- and lanthanum-modified PbTiO3 (PCLT) powders and thin films were prepared by sol-gel processing. Thin films were deposited on Si(100), Si(111), and quartz glass substrates by the coating method. Differential thermal analysis and X-ray diffraction (XRD) patterns show that the perovskite phase of PCLT powders and films was formed at about 500°C. The effects of thickness on phase formation of the thin films were investigated using XRD, and the phase formation was found to be related to film thickness. The degree of grain orientation of thicker films was lower than that of thin films, and the grain size of the thick films was larger. Raman spectra indicated that the phase of the film on the Si(100) substrate was tetragonal in nature, and the mechanisms of shift and broadening of the Raman phonon frequencies in PCLT film are discussed. Scanning electron microscopy revealed that the films on silicon substrates were crack-free and smooth in surface.