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

• Monocrystal anatase TiO2 films were deposited by the MOCVD method.
• The crystalline quality, epitaxial relationship and microstructure were studied.
• The films showed excellent transparency of 70–80% in the visible range.

High-quality single-crystal anatase TiO2(a-TiO2) thin films have been obtained on SrTiO3 (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−2θ 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-TiO2 (001)||STO (100) with a-TiO2 [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 TiO2. The samples showed high transparency of 70–80% in the visible range.