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Chemiresistive gas sensing properties of Fe2O3 thin films have been investigated. The sensor films were prepared by oxidation of Fe films, deposited by electron-beam evaporation method on sapphire substrates. We demonstrate that these films exhibit reversible response towards H2S in the concentration range of 1-50 ppm, with fast response and recovery times. Modification of these films by Au resulted in the enhancement of response towards H2S. Au, as a sensitizer helps in improving the sensors response by a spill-over effect. [ABSTRACT FROM AUTHOR]

Gas sensing properties of pure and Au incorporated WO3 thin films towards H2S and Cl2 have been investigated. The sensor films were able to detect H2S and Cl2 selectively at an operating temperature of 150 and 200 °C, respectively. Effect of gas concentration and Au loading have been investigated and correlated with the observed sensitivity values. Pure WO3 films exhibited better sensing characteristics towards H2S (S = 17, 10 ppm, 150 °C) while sensor film containing Au thickness of 21.6 nm exhibited a maximum sensitivity towards Cl2 (S = 89, 10 ppm, 200 °C).. [ABSTRACT FROM AUTHOR]