Benzene detection on nanostructured tungsten oxide MEMS based gas sensors

Gas sensor devices based on tungsten oxide films, grown directly on MEMS based substrates at 400°C via AACVD, are tested towards low concentrations of benzene. Analysis of the films show they are composed of randomly orientated nanoneedles with strong preferential orientation. These films are sensitive to benzene even at low (1 ppm) concentration and at moderate sensor operating temperatures (between 150 and 250°C). Sensitivity of films is attributed to the particular morphology and structure of the film and the formation of higher fraction of oxygen vacancies at the surface of the nanoneedles, compared to polycrystalline films.