Improving the hydrogen gas sensing performance of Pt/MoO3 nanoplatelets using a nano thick layer of La2O3

Shafiei, M., Yu, J., Chen, G., Lai, P.T., Motta, N., Wlodarski, W., & Kalantar-zadeh, K. (2013) Improving the hydrogen gas sensing performance of Pt/MoO3 nanoplatelets using a nano thick layer of La2O3. Sensors and Actuators B : Chemical, 187, pp. 267-273.

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In this paper, we present how a thin RF sputtered layer of lanthanum oxide (La2O3) can alter electrical and improve hydrogen gas sensing characteristics of Pt/molybdenum oxide (MoO3) nanostructures Schottky diodes. We derived the barrier height, ideality factor and dielectric constant from the measured I–V characteristics at operating temperatures in the range of 25–300 ◦C. The dynamic response, response and recovery times were obtained upon exposure to hydrogen gas at different concentrations. Analysis of the results indicated a substantial improvement to the voltage shift sensitivity of the sensors incorporating the La2O3 layer. We associate this enhancement to the formation of numerous trap states due to the presence of the La2O3 thin film on the MoO3 nanoplatelets. These trap states increase the intensity of the dipolar charges at the metal–semiconductor interface, which induce greater bending of the energy bands. However, results also indicate that the presence of La2O3 trap states also increases response and recover times as electrons trapping and de-trapping processes occur before they can pass through this thin dielectric layer.

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ID Code: 58911
Item Type: Journal Article
Refereed: Yes
Keywords: Gas sensor, Hydrogen, Nanostructures, Lanthanum oxide, Molybdenum oxide, Localized states
DOI: 10.1016/j.snb.2012.11.019
ISSN: 0925-4005
Subjects: Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > ANALYTICAL CHEMISTRY (030100) > Sensor Technology (Chemical aspects) (030107)
Australian and New Zealand Standard Research Classification > TECHNOLOGY (100000) > NANOTECHNOLOGY (100700) > Nanomaterials (100708)
Australian and New Zealand Standard Research Classification > TECHNOLOGY (100000) > NANOTECHNOLOGY (100700) > Nanoscale Characterisation (100712)
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: NOTICE: 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, [Volume 187, (October 2013)] DOI: 10.1016/j.snb.2012.11.019
Deposited On: 11 Apr 2013 22:49
Last Modified: 03 Nov 2015 20:50

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