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Erratum published on 21 February 2019, see Coatings 2019, 9(2), 142.
Open AccessArticle

Optimised Performance of Non-Dispersive Infrared Gas Sensors Using Multilayer Thin Film Bandpass Filters

1
School of OptoElectronic Engineering, Changchun University of Science and Technology, Changchun 130012, China
2
Scottish Universities Physics Alliance (SUPA), The Institute for Thin Films, Sensors & Imaging, University of the West of Scotland, Paisley PA1 2BE, UK
3
Gas Sensing Solutions Ltd., 60-62 Grayshill Road Westfield North Courtyard, Cumbernauld G68 9HQ, UK
4
Scottish Universities Physics Alliance (SUPA), School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK
*
Authors to whom correspondence should be addressed.
Coatings 2018, 8(12), 472; https://doi.org/10.3390/coatings8120472
Received: 5 October 2018 / Revised: 6 December 2018 / Accepted: 14 December 2018 / Published: 19 December 2018
(This article belongs to the Special Issue Applications of Optical Thin Film Coatings)
In this work, performance improvements are described for a low-power consumption non-dispersive infrared (NDIR) methane (CH4) gas sensor using customised optical thin film bandpass filters (BPFs) centered at 3300 nm. BPFs shape the spectral characteristics of the combined mid-infrared III–V based light emitting diode (LED)/photodiode (PD) light source/detector optopair, enhancing the NDIR CH4 sensor performance. The BPFs, deposited using a novel microwave plasma-assisted pulsed DC sputter deposition process, provide room temperature deposition directly onto the temperature-sensitive PD heterostructure. BPFs comprise germanium (Ge) and niobium pentoxide (Nb2O5) alternating high and low refractive index layers, respectively. Two different optical filter designs are progressed with BPF bandwidths (BWs) of 160 and 300 nm. A comparison of the modelled and measured NDIR sensor performance is described, highlighting the maximised signal-to-noise ratio (SNR) and the minimised cross-talk performance benefits. The BPF spectral stability for various environmental temperature and humidity conditions is demonstrated. View Full-Text
Keywords: NDIR; methane; sensor; infrared; thin film; III–V; heterostructure; bandpass; microwave; sputter; MBE NDIR; methane; sensor; infrared; thin film; III–V; heterostructure; bandpass; microwave; sputter; MBE
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Wang, P.; Fu, X.; Gibson, D.; Fleming, L.; Ahmadzadeh, S.; Li, C.; Muhiyudin, M.; Song, S.; Hutson, D.; Moodie, D.; MacGregor, C.; Steer, M. Optimised Performance of Non-Dispersive Infrared Gas Sensors Using Multilayer Thin Film Bandpass Filters. Coatings 2018, 8, 472.

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