Enhanced H2S sensing characteristics of Au modified Fe2O3 thin films

•Surface modification was successfully achieved by sputtering Au.•Au modified (2.33at% Au) films exhibit enhanced and selective response towards H2S with an n-type conductivity.•Sensing mechanism based on spillover effect and formation of nano-Schottky barriers has been proposed. H2S sensing charact...

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Bibliographic Details
Published in:Sensors and actuators. B, Chemical Chemical, 2015-11, Vol.219, p.125-132
Main Authors: Balouria, Vishal, Ramgir, Niranjan S., Singh, A., Debnath, A.K., Mahajan, Aman, Bedi, R.K., Aswal, D.K., Gupta, S.K.
Format: Article
Language:English
Subjects:
Fe2O3 thin films
H2S sensor
Nano-Schottky barrier
Surface modification
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Summary:•Surface modification was successfully achieved by sputtering Au.•Au modified (2.33at% Au) films exhibit enhanced and selective response towards H2S with an n-type conductivity.•Sensing mechanism based on spillover effect and formation of nano-Schottky barriers has been proposed. H2S sensing characteristics of pure and Au modified Fe2O3 thin films have been investigated. Fe2O3 thin films were realized in two steps; first pure Fe films were deposited using electron-beam evaporation method and subsequently subjected to oxidation at 800°C in O2 environment. Surface modification with Au was achieved by employing RF sputtering. Both pure and Au modified Fe2O3 samples exhibited an n-type conductivity pattern. Modification with 2.33at% of Au resulted in an enhanced response of 538% towards 10ppm of H2S at 250°C, with response and recovery times of 1.65 and 27min, respectively. The enhanced response has been attributed mainly to the dual role of Au i.e., forming nano-Schottky barriers with the host Fe2O3 matrix and as a promoter for the spillover effect.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2015.04.113