On-the-Fly Calibration of Low-Cost Gas Sensors

Abstract In this study, porous silicon (PSi) was used to manufacture gas sensors for acetone and ethanol. Samples of PSi were successfully prepared by photoelectrochemical etching and applied as an acetone and ethanol gas sensor at room temperature at various current densities J= 12, 24 and 30 mA/cm2 with an etching time of 10 min and hydrofluoric acid concentration of 40%. Well-ordered n-type PSi (100) was carefully studied for its chemical composition, surface structure and bond configuration of the surface via X-ray diffraction, atomic force microscopy, Fourier transform infrared spectroscopy and photoluminescence tests. Results showed that the best sensitivity of PSi was to acetone gas than to ethanol under the same conditions at an etching current density of 30 mA/cm2, reaching about 2.413 at a concentration of 500 parts per million. The PSi layers served as low-cost and high-quality acetone gas sensors. Thus, PSi can be used to replace expensive materials used in gas sensors that function at low temperatures, including room temperature. The material has an exceptionally high surface-to-volume ratio (increasing surface area) and demonstrates ease of fabrication and compatibility with manufacturing processes of silicon microelectronics.

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A two-stage method for real-time baseline drift compensation in gas sensors

Measurement Science and Technology ◽

10.1088/1361-6501/ac491f ◽

2022 ◽

Author(s):

Chao Zhang ◽

Wen Wang ◽

Pan Yong ◽

Lina Cheng ◽

Shoupei Zhai ◽

...

Keyword(s):

Real Time ◽

Gas Sensors ◽

Piecewise Linear ◽

Low Cost ◽

Piecewise Linear Approximation ◽

Two Stage ◽

Baseline Drift ◽

Ambient Temperatures ◽

Future Design ◽

Drift Compensation

Abstract Baseline drift caused by slowly changing environment and other instability factors affects significantly the performance of gas sensors, resulting in reduced accuracy of gas classification and quantification of the electronic nose. In this work, a two-stage method is proposed for real-time sensor baseline drift compensation based on estimation theory and piecewise linear approximation. In the first stage, the linear information from the baseline before exposure is extracted for prediction. The second stage continuously predicts changing linear parameters during exposure by combining temperature change information and time series information, and then the baseline drift is compensated by subtracting the predicted baseline from the real sensor response. The proposed method is compared to three efficient algorithms and the experiments are conducted towards two simulated datasets and two surface acoustic wave sensor datasets. The experimental results prove the effectiveness of the proposed algorithm. Moreover, the proposed method can recover the true response signal under different ambient temperatures in real-time, which can guide the future design of low-power and low-cost rapid detection systems.

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Laser forming of LTCC Ceramics for Hot-Plate Gas Sensors

Journal of Microelectronics and Electronic Packaging ◽

10.4071/1551-4897-2.1.14 ◽

2005 ◽

Vol 2 (1) ◽

pp. 14-18 ◽

Cited By ~ 2

Author(s):

Jaroslaw Kita ◽

Frank Rettig ◽

Ralf Moos ◽

Karl-Heinz Drüe ◽

Heiko Thust

Keyword(s):

Power Consumption ◽

Gas Sensors ◽

Low Cost ◽

Sensor Arrays ◽

Beam Width ◽

Laser Forming ◽

Hot Plate ◽

Small Series ◽

Plate Design ◽

Future Work

Hot-plate LTCC gas sensors combine advantages of silicon structures (low power consumption) and typical ceramics gas sensors (stability and reliability). Such elements can be integrated in MEMS packages as well as in ceramic sensor arrays. Moreover, they can be produced in small series with relatively low cost. One important key in hot-plate design are properly formed beams. This paper presents possibilities and problems related to laser forming of LTCC ceramics for hot-plate gas sensors. Influence of beam width on power consumption and temperature distribution is discussed. Possibilities to achieve beam width as narrow as possible are practically tested by laser cutting. Obtained results are very promising for future work and for possible application of LTCC ceramics in such type of gas sensors.

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A Review of Carbon Nanotubes-Based Gas Sensors

Journal of Sensors ◽

10.1155/2009/493904 ◽

2009 ◽

Vol 2009 ◽

pp. 1-24 ◽

Cited By ~ 255

Author(s):

Yun Wang ◽

John T. W. Yeow

Keyword(s):

Carbon Nanotubes ◽

Gas Sensors ◽

Gas Sensing ◽

Low Cost ◽

High Surface ◽

Hollow Structure ◽

Volume Ratio ◽

Fast Response ◽

Sensing Technology ◽

Structure Of Nanomaterials

Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nanotubes (CNTs) has fuelled the inventions of gas sensors that exploit CNTs' unique geometry, morphology, and material properties. Upon exposure to certain gases, the changes in CNTs' properties can be detected by various methods. Therefore, CNTs-based gas sensors and their mechanisms have been widely studied recently. In this paper, a broad but yet in-depth survey of current CNTs-based gas sensing technology is presented. Both experimental works and theoretical simulations are reviewed. The design, fabrication, and the sensing mechanisms of the CNTs-based gas sensors are discussed. The challenges and perspectives of the research are also addressed in this review.

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