Showing papers by "Erwin Maciak published in 2011"

Layered thin film nanostructures of Pd/WO3-x as resistance gas sensors

Abstract: Layered nanostructures of tungsten trioxide WO3-x about 62 nm thick, with a very thin film of palladium (about 3.3 nm) on the top, have been studied for gas-sensing application at temperatures 50◦C and 120–130◦C and low NO2 and NH3 concentrations in 6%, 30% or 45% relative humidity in the air. Thin film WO3-x nanostructures were obtained by vacuum deposition on a common Si-SiO2 substrate at room temperature and 120◦C. The palladium was coated by vacuum evaporation at room temperature and 4 · 10 mbar on WO3-x layers obtained at two different substrate temperatures. The average rate of growth of the films, controlled by a QCM, was 0.1–0.2 nm/s. A multi-channel (four-channel interdigital gold electrodes) planar resistance gas sensor structure was used in the experiments. The surface of the nanostructures was characterized by means of the AFM method. Good sensor results have been observed at these layered nanostructures with an increasing resistance for NO2 molecules and decreasing resistance for NH3 molecules in a humid air atmosphere. The interaction and recovery speed were higher in the case of the nanostructure obtained at room temperature.