THE GAS-SENSING PROPERTIES OF TIN OXIDE THIN-FILMS DEPOSITED BY METALLORGANIC CHEMICAL-VAPOR-DEPOSITION

A series of undoped SnO2 films was grown by metallorganic chemical vap or deposition (MOCVD) from an Sn(O(t)Bu)(4) precursor. The characteriz ation of their CO- and H2O-gas sensing properties is reported. The fil ms were very sensitive to low levels of CO at elevated temperatures (2 00 to 400 degrees C), although a significant cross sensitivity to rela tive humidity was found. Response and recovery times were very short i n comparison with a Pt-doped thick film SnO2 pellet. The optimum worki ng temperature was found to be 300 to 350 degrees C, where linear resp onses to CO concentration and to relative humidity were seen once drif t had been taken into account. All MOCVD films tested showed superior responses to a sputtered film.