Comparison of classical and fluctuation-enhanced gas sensing with PdxWO3 nanoparticle films

Nanoparticle films of PdxWO3, with x being 0.01 or 0.12, were made by dual-beam gas evaporation. The stochastic signal component (fluctuation-enhanced signal) originating from resistance fluctuations and the dc resistance (classical sensor signal) were measured during exposure to ethanol and hydrogen gas. For ethanol concentrations exceeding 50 ppm, changes in the resistance fluctuations gave 300 times larger detection sensitivity than changes in the dc resistance.