A Comparison Study on Hydrogen Sensing Performance of MoO3 Nanoplatelets Coated with a Thin Layer of Ta2O5 or La2O3

J. Yu; Y. Liu; F.X. Cai; M. Shafiei; G. Chen; N. Motta; W. Wlodarski; K.  Kalantar-zadeh; P.T. Lai

doi:10.6180/jase.2014.17.1.05

A Comparison Study on Hydrogen Sensing Performance of MoO3 Nanoplatelets Coated with a Thin Layer of Ta2O5 or La2O3

J. Yu This email address is being protected from spambots. You need JavaScript enabled to view it.^1,2,3, Y. Liu^1,2,3, F. X. Cai^1,2,3, M. Shafiei^1,2,3, G. Chen^1,2,3, N. Motta^1,2,3, W. Wlodarski^1,2,3, K. Kalantar-zadeh^1,2,3 and P. T. Lai^1,2,3

¹Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, SAR
²School of Chemistry, Physics and Mechanical Engineering, Institute of Future Environments, Queensland University of Technology, Australia
³School of Electrical and Computer Engineering, RMIT University, Australia

Received: May 24, 2014
Accepted: February 22, 2014
Publication Date: March 1, 2014

Download Citation: ||https://doi.org/10.6180/jase.2014.17.1.05

ABSTRACT

There has been significant interest in developing metal oxide films with high surface area-to-volume ratio nanostructures particularly in substantially increasing the performance of Pt/oxide/semiconductor Schottky-diode gas sensors. While retaining the surface morphology of these devices, they can be further improved by modifying their nanostructured surface with a thin metal oxide layer. In this work, we analyse and compare the electrical and hydrogen-sensing properties of MoO₃ nanoplatelets coated with a 4 nm layer of tantalum oxide (Ta₂O₅) or lanthanum oxide (La₂O₃). We explain in our study, that the presence of numerous defect traps at the surface (and the bulk) of the thin high- layer causes a substantial trapping of charge during hydrogen adsorption. As a result, the interface between the Pt electrode and the thin oxide layer becomes highly polarised. Measurement results also show that the nanoplatelets coated with Ta₂O₅ can enable the device to be more sensitive (a larger voltage shift under hydrogen exposure) than those coated with La₂O₃.

Keywords: Hydrogen, Gas Sensor, Metal Oxide, Heterostructure

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