Metal Oxide Thin Films Prepared by Magnetron Sputtering Technology for Volatile Organic Compound Detection in the Microwave Frequency Range.

Metal oxide thin films such as copper oxide, titanium dioxide, and tin dioxide deposited by magnetron sputtering technology were verified as a gas-sensitive layer in microwave-based gas sensors operated at 2.4 GHz. The developed gas sensors were tested at room temperature (23 °C) and 50% relative humidity (RH) under exposure to 0⁻200 ppm of selected volatile organic compounds (acetone, ethanol, and methanol) that are of high interest in industry and biomedical applications. The highest responses to acetone were obtained for CuO-based gas sensors, to ethanol for SnO₂-based gas sensors, while for methanol detection both dioxides, SnO₂ and TiO₂, exhibited good sensitivity.