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Low-temperature InO x thin films for O 3 and NO 2 gas sensing

2003; SPIE; Volume: 5116; Linguagem: Inglês

10.1117/12.501464

1996-756X

G. Kiriakidis, H. Ouacha, N. Katsarakis, Kosmas Galatsis, Wojtek Wlodarski,

ZnO doping and properties

The desirable electrical properties of InO x thin films and their response towards oxidizing gases has promoted InO x to be recognized as a promising material for gas sensors. In this study, InO x films in the thickness range of 10-1000 nm were deposited onto Corning 7059 glass substrates by dc magnetron sputtering. Their structural, electrical, and O 3 and NO 2 sensing properties were analyzed. Structural investigations carried out by XRD and AFM showed a strong correlation between crystallinity, surface topology and gas sensitivity. Moreover, the electrical conductivity exhibited a change of over six orders of magnitude during the processes of photoreduction and oxidation. The films deposited on alumina transducers were calibrated towards O 3 and NO 2 at temperatures from 50-300 °C. The sensors show promising characteristics as they exhibited reproducible and stable responses. The 50 nm thin film had a response of over 10 towards 50 ppb of ozone operating at 50°C, while the 20 nm film had a response of over 22 towards 0.1 ppm of NO 2 at 100°C.