Influence of Cu/Sn mixture on the shape and structure of crystallites in copper-containing films: Morphological and X-ray spectroscopy studies

The copper-containing SiO2CuOx and SiO2(CuOxSnOy) 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 SnCl4 into the sol. So, the tin adding prevents the formation of the flow-like agglomerates. In accordance with XPS data, CuO, CuO2 and CuSiO3 phases present in the both samples. Adding of the tin decreases the content of CuO2 and increases CuSiO3 on the surface and in volume of the films. The mixed-oxide crystallites are formed in SiO2CuOx and in SiO2(CuOxSnOy) grains consist of copper- oxides and SnO2. Presence of tin oxide particles in the films decreases the response to NO2 gas, but at the same time expands the range of detectable concentrations.