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In the paper the SiO x CuO y thin and thick films were deposited from the alcoholic solutions employing the sol-gel technique. Investigations of films structure and surface morphology are represented. The joint X-ray diffraction and X-ray photoelectron spectroscopy studies reveal presence both CuO and Cu 2 O phases and formation of CuSiO 3 phase with crystallites sizes of 35–50 nm. It is shown that surface roughness of the thin films increases in proportion to the increase of copper content in the precursor. Effective band gap energy estimated from the absorption spectra depends on the film thickness and phase composition. The gas sensitivity tests versus 1–25 ppm of NO 2 showed the dependence of gas sensing response on the film thickness. The operating temperature was 170 °C and 20 °C for thin and thick film sensors, respectively. Accelerated stability tests of the initial resistance and gas sensor response performed high stability and reproducibility of the thin film sensors. [ABSTRACT FROM AUTHOR]

The copper-containing SiO 2 CuO x and SiO 2 (CuO x SnO y ) films were deposited on to oxidized silicon substrates from the alcoholic solutions employing the sol-gel technique. The morphological and structural properties of the films were investigated by the SEM, EDX, XRD, XPS, XAS. The SEM studies have found grain shape changes from flower-like agglomerates to regular shaped inorganic ones as a result of adding the SnCl 4 into the sol. So, the tin adding prevents the formation of the flow-like agglomerates. In accordance with XPS data, CuO, CuO 2 and CuSiO 3 phases present in the both samples. Adding of the tin decreases the content of CuO 2 and increases CuSiO 3 on the surface and in volume of the films. The mixed-oxide crystallites are formed in SiO 2 CuO x and in SiO 2 (CuO x SnO y ) grains consist of copper- oxides and SnO 2 . Presence of tin oxide particles in the films decreases the response to NO 2 gas, but at the same time expands the range of detectable concentrations. [ABSTRACT FROM AUTHOR]