Electronic structure and formation mechanism of complex Ti–Nb oxide

• Published in: Thin solid films Vol. 520; no. 14; pp. 4797 - 4799
• Main Authors: Khoviv, D.A., Zaytsev, S.V., Ievlev, V.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2012
• Subjects: Complex oxide; Magnetron; Niobium oxide; Thin films; Titanium oxide; Trasparent conductive oxide; Thin films; Trasparent conductive oxide; Complex oxide; Magnetron; Titanium oxide; Niobium oxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.10.130

Two-layer thin film specimens of Nb2O5 and TiO2 were deposited on optical-grade quartz and n-type single crystalline silicon substrates with (100) crystallographic orientation by a magnetron deposition source under high vacuum. All samples were subjected to 1–5h of resistive heating at ultra high vacuum, and in situ X-ray diffraction measurements (XRD) were made in the temperature range of 300–1373K. Analysis of the XRD data confirmed the growth of TiNbO4 during cooling of the two-layered specimens which had been previously heated to 1373K. Optical measurements revealed a band gap value of 3.78eV for the direct transition and 3.29eV for the indirect one. The samples had a transmittance of 85% in the visible range. Electrophysical measurements in high vacuum established the electroresistivity vs. temperature dependence in the range of 300–773K, from 7.3⁎10−1 to 3.9⁎10−2Ω cm, respectively. X-ray photoelectron spectroscopy measurements were used to examine the chemical shift for Nb 3d, with a value of −1.1eV in comparison with Nb5+ and matched to Nb4+[1], while the Ti lines correspond to Ti4+[2].