Electrodes for nanodot-based gas sensors

A review with 86 references. Many gas sensors operate by detecting changes in the electrical properties of a sensing film material in the presence of a test gas. The influence of electrode material and geometry on sensitivity and selectivity, as studied by several workers, is discussed. Nanoparticulate sensing films are being reported increasingly, and may display greater sensitivity than films with larger particle sizes. However, gas sensor electrodes generally still have spacings of the order of microns. Some well-established and novel techniques available for fabricating electrodes with spacings similar to nanoparticle diameters are reviewed: photolithography, electron-beam lithography, scanning-probe methods, and 'electrochemical narrowing'.