Ozone detection using low-power-consumption metal–oxide gas sensors

Thin films of RGTO–SnO 2 deposited onto micromachined heater elements were characterised for their sensitivity towards prominent air pollutants such as O 3, NO 2, NO and CO. We find that, unlike their thick-film counterparts, thin-film SnO 2 sensors exhibit a very high sensitivity towards oxidising gases such as NO 2, and in particular O 3. Sensitivities towards reducing species such as CO and NO are less pronounced than in thick-film sensors and in the nature of small cross-sensitivities on the main sensitivity to ozone. The differences between thin and thick-film devices are discussed, and it is shown that thin-film devices on micromachined heater elements hold promise for fabricating low-power-consumption gas sensors capable of detecting environmentally relevant concentrations of ozone.