The Gas‐Sensing Properties of Tin Oxide Thin Films Deposited by Metallorganic Chemical Vapor Deposition

A series of undoped films was grown by metallorganic chemical vapor deposition (MOCVD) from an precursor. The characterization of their CO‐ and ‐gas sensing properties is reported. The films were very sensitive to low levels of CO at elevated temperatures (200 to 400°C), although a significant cross‐sensitivity to relative humidity was found Response and recovery times were very short in comparison with a Pt‐doped thick film pellet. The optimum working temperature was found to be 300 to 350°C, where linear responses to CO concentration and to relative humidity were seen once drift had been taken into account. All MOCVD films tested showed superior responses to a sputtered film.