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

Cadmium- and lanthanum-modified PbTiO3 (PCLT) powders and thin films were p repared by sol-gel processing. Thin films were deposited on Si(100), Si(lll ), and quartz glass substrates by the coating method. Differential thermal analysis and X-ray diffraction (XRD) patterns show that the perovskite phas e of PCLT powders and films was formed at about 500 degrees C. The effects of thickness on phase formation of the thin films were investigated using X RD, 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 fi lms, and the grain size of the thick films was larger. Raman spectra indica ted that the phase of the film on the Si(100) substrate was tetragonal in n ature, and the mechanisms of shift and broadening of the Raman phonon frequ encies in PCLT film are discussed. Scanning electron microscopy revealed th at the films on silicon substrates were crack-free and smooth in surface, ( C) 2000 Elsevier Science Ltd.