Multifunctional air-quality system based on advanced SnO2-sensor-array structures

The selectivity of SnO2-thin-film gas sensors towards various gases can be changed by varying the contact areas of the contact electrodes. Applying this technique it is possible to implement highly selective NO2 sensors. In this work we present test structures and sensor arrays suitable for air quality systems in automobiles and household. The investigated arrays have been structured with two mask steps only. Gas mixture analysis in the german threshold limit value (TLV) range of gases like NO2, CO, CH4 and H20 is possible. Additional doping materials, catalysts, temperature gradients to enhance selectivity are possible but not necessary. Several results of field and laboratory measurements will be presented.