University of Oulu

Rodner, M., Bastuck, M., Schütze, A., Andersson, M., Huotari, J., Puustinen, J., Lappalainen, J., and Sauerwald, T.: Enabling a new method of dynamic field-effect gas sensor operation through lithium-doped tungsten oxide, J. Sens. Sens. Syst., 8, 261–267,, 2019

Enabling a new method of dynamic field-effect gas sensor operation through lithium-doped tungsten oxide

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Author: Rodner, Marius1; Bastuck, Manuel1,2; Schütze, Andreas2;
Organizations: 1Department of Physics, Chemistry and Biology, Linköping University, Linköping, 58183, Sweden
2Lab for Measurement Technologies, University of Saarland, Saarbrücken, 66123, Germany
3Faculty of Information Technology and Electrical Engineering, University of Oulu, Oulu, 90014, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.9 MB)
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Language: English
Published: Copernicus Publications, 2019
Publish Date: 2019-10-16


To fulfil today’s requirements, gas sensors have to become more and more sensitive and selective. Temperature-cycled operation has long been used to enhance the sensitivity and selectivity of metal-oxide semiconductor gas sensors and, more recently, silicon-carbide-based, gas-sensitive field-effect transistors (SiC-FETs). In this work, we present a novel method to significantly enhance the effect of gate bias on a SiC-FET’s response, giving rise to new possibilities for static and transient signal generation and, thus, increased sensitivity and selectivity. A tungsten trioxide (WO₃) layer is deposited via pulsed laser deposition as an oxide layer beneath a porous iridium gate, and is doped with 0.1 AT % of lithium cations. Tests with ammonia as a well-characterized model gas show a relaxation effect with a time constant between 20 and 30 s after a gate bias step as well as significantly increased response and sensitivity at +2 V compared to 0 V. We propose an electric field-mediated change in oxygen surface coverage as the cause of this novel effect.

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Series: Journal of sensors and sensor systems
ISSN: 2194-8771
ISSN-E: 2194-878X
ISSN-L: 2194-8771
Volume: 8
Issue: 2
Pages: 261 - 267
DOI: 10.5194/jsss-8-261-2019
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: We have received support for scientific exchange from the European Cooperation in Science and Technology and support for Open Access Publishing from the Deutsche Forschungsgemeinschaft and Saarland University.
Copyright information: © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.