High-sensitivity electro-optic CO<sub>2</sub> gas sensing based on absorption spectroscopy

2012 ◽  
Author(s):  
Scott N. Zhang ◽  
Dorothy Y. Wang ◽  
Jianmin Gong ◽  
Dian Fan ◽  
Bo Dong ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Electro Optic

Prism-based Broadband Optical Cavity (400 – 1600 nm) for High-Sensitivity Trace Gas Sensing by Cavity Enhanced Absorption Spectroscopy

2020 ◽  
Author(s):  
Weidong Chen ◽  
Gaoxuan Wang ◽  
Lingshuo Meng ◽  
Qian Gou ◽  
Azer Yalin ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Gas Sensing ◽  
Optical Cavity ◽  
Wavelength Region ◽  
High Sensitivity ◽  
Central Wavelength ◽  
Enhanced Absorption ◽  
High Reflectivity ◽  
Cavity Enhanced Absorption Spectroscopy ◽  
High Finesse

&lt;p&gt;The use of high reflectivity dielectric mirrors to form a high finesse optical cavity allows one to achieve long optical path lengths of up to several kilometres for high-sensitivity spectroscopy applications [1]. However, the high reflectivity of a dielectric mirror is achieved via constructive interference of the Fresnel reflection at the interfaces produced by multilayer coatings of alternate high and low refractive index materials. This wavelength-dependent coating limits the bandwidth of the mirror's high reflectivity to only a few percent of the designed central wavelength [2].&lt;/p&gt;&lt;p&gt;In this paper, we report on the development of a novel optical cavity based on prism used as cavity reflector through total internal reflection combined with Brewster angle incidence [3], which offers a high-finesse optical cavity operating in a broadband wavelength region from 400 to longer than 1600 nm. Cavity Enhanced Absorption Spectroscopy (CEAS) of NO&lt;sub&gt;2&lt;/sub&gt;, NO&lt;sub&gt;3&lt;/sub&gt;, and H&lt;sub&gt;2&lt;/sub&gt;O vapor was applied to determine the achieved prism reflectivity over a broad spectral range from 400 nm to 1600 nm.&lt;/p&gt;&lt;p&gt;Experimental details and preliminary results will be presented. The developed prism-based cavity is specifically adapted for the needs of broadband measurement of multi-molecular absorber or/and wavelength-dependent extinction coefficient of aerosols over a broad spectral region.&lt;/p&gt;&lt;p&gt;Acknowledgments. This work is supported by the French national research agency (ANR) under the CaPPA (ANR-10-LABX-005), the MABCaM (ANR-16-CE04-0009) and the MULTIPAS (ANR-16-CE04-0012) contracts. The authors thank the financial support from the CPER CLIMIBIO program.&lt;/p&gt;&lt;p&gt;REFERENCES&lt;/p&gt;&lt;p&gt;[1] S. S. Brown, &quot;Absorption spectroscopy in high-finesse cavities for atmospheric studies&quot;, Chem. Rev. &lt;strong&gt;103&lt;/strong&gt; (2003) 5219-5238.&lt;/p&gt;&lt;p&gt;[2] G.R. Fowles, Introduction to Modern Optics, 2nd ed. (Rinehart and Winston, 1975), p. 328.&lt;/p&gt;&lt;p&gt;[3] B. Lee, K. Lehmann, J. Taylor and A. Yalin, &quot;A high-finesse broadband optical cavity using calcium fluoride prism retroreflectors&quot;, Opt. Express &lt;strong&gt;2&lt;/strong&gt;&lt;strong&gt;2&lt;/strong&gt; (2014) 11583-11591.&lt;/p&gt;

Schottky diodes based on 2D materials for environmental gas monitoring: a review on emerging trends, recent developments and future perspectives

2021 ◽  
Author(s):  
Minu Mathew ◽  
Chandra Sekhar Rout
Keyword(s):  
Gas Sensing ◽  
2D Materials ◽  
Schottky Diodes ◽  
High Sensitivity ◽  
Future Perspectives ◽  
Working Temperature ◽  
Emerging Trends ◽  
Gas Sensing Properties ◽  
Recent Developments ◽  
Sensitivity And Selectivity

This review details the fundamentals, working principles and recent developments of Schottky junctions based on 2D materials to emphasize their improved gas sensing properties including low working temperature, high sensitivity, and selectivity.

Halogenated hydrocarbon gas sensing by rotational absorption spectroscopy in the 220–330 GHz frequency range

2021 ◽  
Vol 127 (8) ◽  
Author(s):  
T. E. Rice ◽  
M. A. Z. Chowdhury ◽  
M. W. Mansha ◽  
M. M. Hella ◽  
I. Wilke ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Gas Sensing ◽  
Frequency Range ◽  
Halogenated Hydrocarbon ◽  
Hydrocarbon Gas

High Sensitivity Heterodyne Electro-Optic Sampling with 1.5-µm Laser Source

2019 ◽  
Author(s):  
Hideaki Kitahara ◽  
Hiroyuki Kato ◽  
Masaki Shiihara ◽  
Akihiro Esaki ◽  
Kohji Yamamoto ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Laser Source ◽  
Electro Optic

scholarly journals Spatially Ordered Matrix of Nanostructured Tin–Tungsten Oxides Nanocomposites Formed by Ionic Layer Deposition for Gas Sensing

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4169
Author(s):  
Gennady Gorokh ◽  
Natalia Bogomazova ◽  
Abdelhafed Taleb ◽  
Valery Zhylinski ◽  
Timur Galkovsky ◽  
...  
Keyword(s):  
Tungsten Oxide ◽  
Gas Sensing ◽  
Oxide Films ◽  
High Sensitivity ◽  
Anodic Alumina ◽  
Film Deposition ◽  
Silicon Substrates ◽  
Layer By Layer ◽  
Gas Sensitivity ◽  
Nanoporous Anodic Alumina

The process of layer-by-layer ionic deposition of tin-tungsten oxide films on smooth silicon substrates and nanoporous anodic alumina matrices has been studied. To achieve the film deposition, solutions containing cationic SnF2 or SnCl2 and anionic Na2WO4 or (NH4)2O·WO3 precursors have been used. The effect of the solution compositions on the films deposition rates, morphology, composition, and properties was investigated. Possible mechanisms of tin-tungsten oxide films deposition into the pores and on the surface of anodic alumina are discussed. The electro-physical and gas-sensitive properties of nanostructured SnxWyOz films have been investigated. The prepared nanocomposites exhibit stable semiconductor properties characterized by high resistance and low temperature coefficient of electrical resistance of about 1.6 × 10−3 K−1. The sensitivity of the SnxWyOz films to 2 and 10 ppm concentrations of ammonia at 523 K was 0.35 and 1.17, respectively. At concentrations of 1 and 2 ppm of nitrogen dioxide, the sensitivity was 0.48 and 1.4, respectively, at a temperature of 473 K. At the temperature of 573 K, the sensitivity of 1.3 was obtained for 100 ppm of ethanol. The prepared nanostructured tin-tungsten oxide films showed promising gas-sensitivity, which makes them a good candidate for the manufacturing of gas sensors with high sensitivity and low power consumption.

Polyaniline/SnO2 Nanocomposite Sensor for NO2 Gas Sensing at Low Operating Temperature

2015 ◽  
Vol 14 (04) ◽  
pp. 1550011 ◽  
Author(s):  
A. Sharma ◽  
M. Tomar ◽  
V. Gupta ◽  
A. Badola ◽  
N. Goswami
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Sensing Properties ◽  
Response Recovery ◽  
Transmission Electron ◽  
Gas Sensing Properties

In this paper gas sensing properties of 0.5–3% polyaniline (PAni) doped SnO 2 thin films sensors prepared by chemical route have been studied towards the trace level detection of NO 2 gas. The structural, optical and surface morphological properties of the PAni doped SnO 2 thin films were investigated by performing X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Raman spectroscopy measurements. A good correlation has been identified between the microstructural and gas sensing properties of these prepared sensors. Out of these films, 1% PAni doped SnO 2 sensor showed high sensitivity towards NO 2 gas along with a sensitivity of 3.01 × 102 at 40°C for 10 ppm of gas. On exposure to NO 2 gas, resistance of all sensors increased to a large extent, even greater than three orders of magnitude. These changes in resistance upon removal of NO 2 gas are found to be reversible in nature and the prepared composite film sensors showed good sensitivity with relatively faster response/recovery speeds.

scholarly journals MWCNT Devices Fabricated by Dielectrophoresis: Study of Their Electrical Behavior Related to Deposited Nanotube Amount for Gas Sensing Applications

2015 ◽  
Vol 10 (1) ◽  
pp. 13-20
Author(s):  
Elisabete Galeazzo ◽  
Marcos C. Moraes ◽  
Henrique E. M. Peres ◽  
Michel O. S. Dantas ◽  
Victor G. C. Lobo ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Cost Effective ◽  
Adsorbed Water ◽  
Fast Response ◽  
Process Time ◽  
Electrical Behavior ◽  
Glass Substrates ◽  
Sensing Applications

Intensive research has been focused on investigating new sensing materials, such as carbon nanotubes (CNT) because of their promising characteristics. However, there are challenges related to their application in commercial devices such as sensitivity, compatibility, and complexity of miniaturization, among others. We report the study of the electrical behavior of devices composed by multi-walled carbon nanotubes (MWCNT) deposited between aluminum electrodes on glass substrates by means of dielectrophoresis (DEP), which is a simple and cost-effective method. The devices were fabricated by varying the DEP process time. Remarkable changes in their electric resistance were noticed depending on the MWCNT quantities deposited. Other electrical properties of devices such as high sensitivity, fast response time and stability are also characterized in humid environment. A humidity sensing mechanism is proposed on the basis of charge transfer between adsorbed water molecules and the MWNTC surface or between water and the glass surface.

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