Selectively arranged single-wire based nanosensor array systems for gas monitoring

Abstract

Gas nanosensors, comprised of arrays of nanoelectrodes with finger-widths of ∼100 nm developed by electron beam lithography and aerosol assisted chemical vapor deposited non-functionalized and Pt-functionalized tungsten oxide nanowires (<100 nm) subsequently integrated across the pairs of electrodes via the dielectrophoresis method, are developed in this work. The functionality of these devices is validated towards various concentrations of NO₂ and C₂H₅OH. The results demonstrate reproducible and consistent responses with better sensitivity and partial selectivity for the non-functionalized systems to NO₂, as opposed to the Pt-functionalized systems, which display better sensing properties towards C₂H₅OH with a loss of response to NO₂. These results are explained on the basis of the additional chemical and electronic interactions at the Pt/tungsten oxide interface, which increase the pre-adsorption of oxygen species and make the functionalized surface rather more sensitive to C₂H₅OH than to NO₂, in contrast to the non-functionalized surface.