Enhanced infra-red emission from sub-millimeter microelectromechanical systems micro hotplates via inkjet deposited carbon nanoparticles and fullerenes

Luca, Andrea De; Cole, Matthew T.; Fasoli, Andrea; Ali, Syed Zeeshan; Udrea, F.; Milne, W. I.

doi:10.1063/1.4809546

Cited by 23 publications

(20 citation statements)

References 29 publications

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“…Although readily available, bulbs provide a cumbersome radiation source, compared to newer technology such as micro hotplates. In particular, SOI IR emitters have greater reliability, faster response and smaller physical dimensions [14,15]. Exhaled gas is difficult to store and transport [16], thus sampling breath-by-breath is our preferred method.…”

Section: Ndir Sensorsmentioning

confidence: 99%

A low cost MEMS based NDIR system for the monitoring of carbon dioxide in breath analysis at ppm levels

Vincent

Gardner

2016

Sensors and Actuators B: Chemical

145

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Please cite this article as: T.A.Vincent, J.W.Gardner, A low cost MEMS based NDIR system for the monitoring of carbon dioxide in breath analysis at ppm levels, Sensors and Actuators B: Chemical http://dx.doi.org/10. 1016/j.snb.2016.04.016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A low cost MEMS based NDIR system for the monitoring of carbon dioxide in breath analysis at ppm levels Highlights  MEMS based NDIR system for ppm CO2 detection with lock-in amplifier.  Fast 1.3 s response time for breath-by-breath analysis.  Portable breath analyser designed for measuring metabolic rate of subjects.  Effect of path length on NDIR system investigated with novel sensor housing.  Silicon on insulator IR emitter used for low power, low cost gas detection. AbstractThe molecules in our breath can provide a wealth of information about the health and well-being of a person. The level of carbon dioxide (CO2) is not only a sign of life but also when combined with the level of exhaled oxygen provides valuable health information in the form of our metabolic rate. We report upon the development of a MEMS-based non-dispersive infrared CO2 sensor for inclusion in a hand held portable breath analyser. Our novel sensor system comprises a thermopile detector and low power MEMS silicon on insulator (SOI) wideband infrared (IR) emitter. A lock-in amplifier design permits a CO2 concentration of 50 ppm to be detected on gas bench rig. Different IR path lengths were studied with gases in dry and humid (25 % and 50 % RH) in order to design a sensor suitable for detecting CO2 in breath with concentrations in the range of 4 to 5 %. A breath analyser was constructed from acetal and in part 3D printed with a side-stream sampling mechanism and tested on a range of subjects with two data-sets presented here. The performance of the novel MEMS based sensor was validated using a reference commercial breath-by-breath sensor and produced comparable results and gave a response time of 1.3 s. Further work involves the detection of other compounds on breath for further metabolic analysis and reducing the overall resolution of our MEMS sensor system from ca. 250 ppm to 10 ppm.

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Section: Ndir Sensorsmentioning

confidence: 99%

A low cost MEMS based NDIR system for the monitoring of carbon dioxide in breath analysis at ppm levels

Vincent

Gardner

2016

Sensors and Actuators B: Chemical

145

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“…r temperature does not ut in the CO 2 absorption k's equation. We have ntally observed that the sivity, of our emitters is m [18]. Herein, we employ h have high wavelengthance the thermo-optical mprovement was assessed t of a commercial high 5, Excelitas) to a CNTin the presence of 100% er and the detector were rical chamber ~7 cm apart using digital mass flow cat).…”

Section: Cnt Growth and Charactementioning

confidence: 99%

In-Situ grown carbon nanotubes for enhanced CO<inf>2</inf> detection in non-dispersive-infra-red system

et al. 2013

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Non-dispersive-infra-red (NDIR) sensors are believed to be one of the most selective and robust solutions for CO 2 detection, though cost prohibits their broader integration. In this paper we propose a commercially viable silicon-oninsulator (SOI) complementary metal-oxide (CMOS) microelectro-mechanical (MEMS) technology for an IR thermal emitter. For the first time, vertically aligned multi walled carbon nanotubes (VA-MWCNTs) are suggested as a possible coating for the enhancement of the emission intensity of the optical source of a NDIR system. VA-MWCNTs have been grown in situ by chemical vapour deposition (CVD) exclusively on the heater area. Optical microscopy, scanning electron microscopy and Raman spectroscopy have been used to verify the quality of the VA-MWCNTs growth. The CNT-coated emitter demonstrated an increased response to CO 2 of approx. 60%. Furthermore, we show that the VA-MWCNTs are stable up to temperatures of 500 °C for up to 100 hours.

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“…The coupling between CMOS technologies and micromachining fabrication techniques offers one viable and attractive route to achieve high-throughput manufacturing, in a cost efficient production process. Nevertheless, materials commonly used in CMOS foundries are often not pyroelectric and have poor IR absorption properties especially for wavelengths < 8 µm, 3 a spectral window of importance for NDIR gas sensing (e.g. methane and CO 2 ).…”

Section: Manuscriptmentioning

confidence: 99%

Enhanced spectroscopic gas sensors using in-situ grown carbon nanotubes

Luca

Cole

Hopper

et al. 2015

Applied Physics Letters

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In this letter we present a fully complementary-metal-oxide-semiconductor (CMOS) compatible microelectromechanical system (MEMS) thermopile infrared (IR) detector employing vertically aligned multi-walled carbon nanotubes (CNT) as an advanced nano-engineered radiation absorbing material. The detector was fabricated using a commercial silicon-on-insulator (SOI) process with tungsten metallization; comprising a silicon thermopile and a tungsten resistive micro-heater, both embedded within a dielectric membrane formed by a deep-reactive ion etch following CMOS processing. In-situ CNT growth on the device was achieved by direct thermal chemical vapour deposition (T-CVD) using the integrated micro-heater as a micro-reactor. The growth of the CNT absorption layer was verified through scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The functional effects of the nanostructured ad-layer were assessed by comparing CNT-coated thermopiles to uncoated thermopiles. Fourier transform infrared (FTIR) spectroscopy showed that the radiation absorbing properties of the CNT adlayer significantly enhanced the absorptivity, compared with the uncoated thermopile, across the IR spectrum (3 μm-15.5 μm). This led to a four-fold amplification of the detected infrared signal (4.26 µm) in a CO 2 non-dispersive-infra-red (NDIR) gas sensor system. The presence of the CNT layer was shown not to degrade the robustness of the uncoated devices; whilst the 50 % modulation depth of the detector was only marginally reduced by 1.5 Hz. Moreover, we find that the 50 % normalized absorption angular profile is

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Enhanced infra-red emission from sub-millimeter microelectromechanical systems micro hotplates via inkjet deposited carbon nanoparticles and fullerenes

Cited by 23 publications

References 29 publications

A low cost MEMS based NDIR system for the monitoring of carbon dioxide in breath analysis at ppm levels

A low cost MEMS based NDIR system for the monitoring of carbon dioxide in breath analysis at ppm levels

In-Situ grown carbon nanotubes for enhanced CO<inf>2</inf> detection in non-dispersive-infra-red system

Enhanced spectroscopic gas sensors using in-situ grown carbon nanotubes

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