Structural and optical properties of anatase TiO2 heteroepitaxial films prepared by MOCVD.

High-quality single-crystal anatase TiO 2(a-TiO 2) thin films have been obtained on SrTiO 3 (STO) substrates using the metalorganic chemical vapor deposition (MOCVD) method. The optimal preparation process was explored. The lattice structure and epitaxial relationship were investigated by X-ray diffraction (XRD, both θ −2 θ and Φ scans) and transmission electron microscopy (TEM). The results indicated that the film prepared at 550 °C with the Ti precursor molar flow rate of 4×10 −7 mol/min had the best single crystalline quality, for which a clear epitaxial relationship of a-TiO 2 (001)||STO (100) with a-TiO 2 [100]||STO [001¯] could be inferred. The elemental composition and proportion were studied by the X-ray photoelectron spectroscopy (XPS) method, which proved the deposited film approximated stoichiometric TiO 2 . The samples showed high transparency of 70–80% in the visible range. [ABSTRACT FROM AUTHOR]