Highly sensitive and multidimensional detection of NO₂ using In₂O₃ thin films

We report on the ultrasensitive and unique detection of NO₂ with respect to common gaseous interferents through multi-dimensional signature analysis using In₂O₃ thin films as sensing layers. Sensor devices fabricated using interdigitated metal fingers of Ti/Au deposited on the In₂O₃ film resulted in...

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Bibliographic Details
Published in:Sensors and actuators. B, Chemical Chemical, 2011-12, Vol.160 (1), p.251-259
Main Authors: Nomani, Md. W.K, Kersey, D, James, J, Diwan, D, Vogt, T, Webb, Richard A, Koley, G
Format: Article
Language:English
Subjects:
adsorption
ammonia
capacitance
Conductance
gases
gold
Indium oxides
Nitrogen dioxide
Sensors
Signatures
Surface chemistry
Thin films
Two dimensional
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Summary:We report on the ultrasensitive and unique detection of NO₂ with respect to common gaseous interferents through multi-dimensional signature analysis using In₂O₃ thin films as sensing layers. Sensor devices fabricated using interdigitated metal fingers of Ti/Au deposited on the In₂O₃ film resulted in extremely high sensitivity for NO₂ molecules, producing 20% change in conductance for 20ppb NO₂ in atmospheric conditions. Molecular adsorption induced changes in conductance (G), capacitance (C), and surface work function (ϕ) upon exposure to various gases were measured to obtain their respective C–G and ϕ–G plots. We observed that the gradients of the (C–G) and (ϕ–G) plots are distinct for individual analytes and can thus can be utilized for the specific detection of molecules. Three dimensional G–C–ϕ signature plots for NO₂ and NH₃ were found to be even more effective than 2D plots in uniquely identifying the gases. Utilization of 2D signatures to analyze a binary gas mixture was found to be quite promising with a large application potential.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2011.07.044