Photochemical synthesis of AZrO3-x thin films (A=Ba, Ca and Sr) and their characterization

(Ba, Ca, Sr)ZrO3-x thin films were prepared by a photochemical method using thin films of beta-diketonate complexes as precursors. The photolysis of these films induces the fragmentation of the 2,2,6,6-tetramethyl-3,5-heptanedionate ligand and the partial reduction of metal ion together with volatile organic compounds as sub-products. When the metallic complexes are irradiated in air, the final product of the reaction are ternary metal oxides. The photoreactivity of these films was monitored by FT-IR spectroscopy by a period of 72 h, followed by post-annealing at 950 degrees C. X-ray photoelectron spectroscopy and X-ray diffraction techniques were used to analyze the chemical composition and the crystalline structure of the films obtained. The results indicate that Ba, Ca, Sr, Zr and O are present in the form of perovskita, preferably adopting an amorphous structure. The surface morphology examined by atomic force microscopy revealed a rough and irregular surface. The UV-vis measurements suggest a slight increase in the optical band gap values, which promote a reduction of the intermediary energy levels or defects. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.