CO sensing properties of W-Mo and tin oxide RGTO multiple layers structures

The possibility to increase the surface-to-volume ratio of tin di-oxide thin films deposited through the RGTO technique is investigated. A novel strategy was used to increase the surface roughness and to exploit the catalytic and sensing properties of a W–Mo layer. Deposition consists in four steps: deposition by sputtering of W–Mo layer, first annealing process, deposition of metallic Sn, second annealing process. Electrical characterization shows a considerable increase in the conductivity of the combined layers and also an increase in the interactivity of the double layer compared to either pure SnO2 or W–Mo oxide layers. This can be ascribed both to the increase in the surface to volume ratio and to the catalytic effect of W and Mo oxide.