Metal oxide gas sensor array for air qualitiy monitoring

Two novel silicon-based sensor arrays for on-line air quality monitoring are described, the first one based on films deposited onto bulk silicon wafers and the second one a novel micromachined device for low power consumption. The micromachined version reduces the power consumption from 1.6 W to 0.26 W at 350 degreesC working temperature. The sensing elements (Cr1.8Ti0.2O3+z, ZnO, SnO2, WO3, V2O5) examined in the arrays include four different metal oxides deposited by thin film technologies. The measured responses in lab and application tests provide patterns which correlate with the air quality and are thus appropriate for an on-line air quality monitoring.