Improved hydrogen gas sensing performance of WO3 films with fibrous nanostructured surface

Abstract

Characteristic fibrous nanostructure, known as fuzz, is formed by a helium plasma exposure of metal surfaces at certain temperatures. Applications of He-induced nanostructure to catalysts and sensors are promising because of its remarkably increased surface area. In this study, WO3 thin films with the fibrous nanostructure were prepared and their performance as a semiconductor-type gas sensor to trace hydrogen gas was evaluated. Change in the electrical resistivity between electrodes on the surface during a 100 ppm hydrogen gas flow and a dry air flow was measured at a sample temperature of 200 °C to 400 °C. Remarkably improved sensitivities compared with a plane WO3 film sensor were observed for fuzzy WO3 film sensors. The highest response of 99.5% was achieved at the ambient temperature of 300 °C.