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Gas sensing characteristics of Fe-doped tungsten oxide thin films

Tesfamichael, Tuquabo, Ponzoni , Andrea, Ahsan, Mohammed, & Faglia , Guido (2012) Gas sensing characteristics of Fe-doped tungsten oxide thin films. Sensors and Actuators B : Chemical, 168, pp. 345-353.

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Abstract

This study reports on the gas sensing characteristics of Fe-doped (10 at.%) tungsten oxide thin films of various thicknesses (100–500 nm) prepared by electron beam evaporation. The performance of these films in sensing four gases (H2, NH3, NO2 and N2O) in the concentration range 2–10,000 ppm at operating temperatures of 150–280 °C has been investigated. The results are compared with the sensing performance of a pure WO3 film of thickness 300 nm produced by the same method. Doping of the tungsten oxide film with 10 at.% Fe significantly increases the base conductance of the pure film but decreases the gas sensing response. The maximum response measured in this experiment, represented by the relative change in resistance when exposed to a gas, was ΔR/R = 375. This was the response amplitude measured in the presence of 5 ppm NO2 at an operating temperature of 250 °C using a 400 nm thick WO3:Fe film. This value is slightly lower than the corresponding result obtained using the pure WO3 film (ΔR/R = 450). However it was noted that the WO3:Fe sensor is highly selective to NO2, exhibiting a much higher response to NO2 compared to the other gases. The high performance of the sensors to NO2 was attributed to the small grain size and high porosity of the films, which was obtained through e-beam evaporation and post-deposition heat treatment of the films at 300 °C for 1 h in air.

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5 citations in Web of Science®

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ID Code: 50309
Item Type: Journal Article
Keywords: Tungsten oxide, Iron doping, Nanostructured thin films, NO2 gas sensing
DOI: 10.1016/j.snb.2012.04.032
ISSN: 1873-3077 (online) 0925-4005(print)
Subjects: Australian and New Zealand Standard Research Classification > PHYSICAL SCIENCES (020000) > CONDENSED MATTER PHYSICS (020400) > Surfaces and Structural Properties of Condensed Matter (020406)
Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > MATERIALS ENGINEERING (091200) > Materials Engineering not elsewhere classified (091299)
Australian and New Zealand Standard Research Classification > TECHNOLOGY (100000) > NANOTECHNOLOGY (100700)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2012 Elsevier B.V.
Copyright Statement: This is the author’s version of a work that was accepted for publication in Sensors and Actuators B : Chemical. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Sensors and Actuators B : Chemical, [VOL 168, (2012)] DOI: 10.1016/j.snb.2012.04.032
Deposited On: 16 May 2012 12:25
Last Modified: 04 Dec 2013 13:15

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