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 1-5 h of resistive heating at ultra high vacuum, and in situ X-ray diffraction measurements (XRD) were made in the temperature range of 300-1373 K. Analysis of the XRD data confirmed the growth of TiNbO4 during cooling of the two-layered specimens which had been previously heated to 1373 K. Optical measurements revealed a band gap value of 3.78 eV for the direct transition and 3.29 eV 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 300-773 K, from 7.3*10(-1) to 3.9*10(-2) Omega cm, respectively. X-ray photoelectron spectroscopy measurements were used to examine the chemical shift for Nb 3d, with a value of -1.1 eV in comparison with Nb5+ and matched to Nb4+ [1], while the Ti lines correspond to Ti4+ [2]. (C) 2011 Elsevier B.V. All rights reserved.