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Journal ArticleDOI

Fabrication of Microsensor for Detection of Low-Concentration Formaldehyde Gas in Formalin-Treated Fish

01 Dec 2020-IEEE Transactions on Electron Devices (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 67, Iss: 12, pp 5710-5716
TL;DR: In this paper, an ultrafast direct laser patterning technique was used to fabricate a low-cost microsensor and its application for formaldehyde detection was reported, where the patterns of microheater and interdigitated electrodes (IDEs) were realized using laser micromachining techniques by ablation of gold thin film on alumina substrate.
Abstract: Here, an ultrafast direct laser patterning technique to fabricate a low-cost microsensor and its application for formaldehyde detection are reported. The patterns of microheater and interdigitated electrodes (IDEs) were realized using laser micromachining techniques by ablation of gold thin film on alumina substrate. The thin film of gold microheater showed good stability up to 300 °C with a fast response time of 80 s and temperature coefficient of resistance (TCR) was calculated as $1.37\times 10^{-{3}}/^{\circ }\text{C}$ . Moreover, gold microheater exhibited long-term reliability under self-heating mode with a negligible resistance drift $^{-{1}}$ ) to formaldehyde even to detect sub-ppm concentrations with fast response (32 s) and recovery kinetics (72 s). Moreover, the microsensor was also used on-site rapid screening for the detection and quantification of formaldehyde concentration in formalin-treated fish sample.
Citations
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Journal ArticleDOI
TL;DR: In this article, a highly sensitive and selective gas sensor for detecting formaldehyde is reported based on SnO2/ZnO heterospheres designed by atomic layer deposition (ALD).
Abstract: Heterostructures of metal oxide semiconductors have a great promise for chemical gas sensors due to the peculiar properties at the heterointerface. In this work, a highly sensitive and selective gas sensor for detecting formaldehyde is reported based on SnO2/ZnO heterospheres designed by atomic layer deposition (ALD). The electronic properties at the SnO2/ZnO heterointerface can be modulated by optimizing the loading of ZnO through changing ALD cycles. Gas sensing tests indicate that the ZnO ALD significantly improved the sensor properties including higher responses, faster response-recovery dynamics and better selectivity. The response of the SnO2/ZnO sensor to 1 ppm formaldehyde (Ra/Rg = 9.7) shows 4 times enhancement compared to pristine SnO2 at a working temperature of 200 °C. ZnO ALD of 10 cycles leads to the best response and recovery dynamics (12 and 24 s), and that of 15 ALD cycles results in the highest response (Ra/Rg = 38.2) to 20 ppm formaldehyde. The SnO2/ZnO sensor also registers a low detection limit of 70 ppb, which allows for reliable detection of sub-ppm formaldehyde. The remarkable sensor performances indicate the ALD surface engineering is promising for the design of new materials for reliable detection of harmful molecules.

87 citations

Journal ArticleDOI
TL;DR: In this article, Fe2O3-sensitized SnO2 nanosheets are designed via atomic layer deposition (ALD) to realize high performance formaldehyde detection, by varying the ALD cycles, the influence of different Fe 2O3 loading on the sensing performance of SnO 2 nanOSheets is revealed.
Abstract: Metal oxide semiconductor (MOS) nanostructures have been widely explored for formaldehyde sensors. The low surface chemical and electronic properties of pure MOS, however, greatly limits the sensor functions. In this work, Fe2O3-sensitized SnO2 nanosheets are designed via atomic layer deposition (ALD) to realize high performance formaldehyde detection. By varying the ALD cycles, the influence of different Fe2O3 loading on the sensing performance of SnO2 nanosheets is revealed. It is found that Fe2O3 ALD can greatly boost the sensing performance and the SnO2 nanosheets with 20 Fe2O3 ALD cycles exhibits the best response (Ra/Rg = 4.5) and fast response and recovery dynamics (9 and 34 s) to 20 ppm formaldehyde at a relative low temperature of 220 °C. The sensor based on SnO2/Fe2O3 also displays good selectivity to formaldehyde as well as the reliable stability and low limit of detection (LOD). This work will shed some light to design efficient MOS heterostructures for detection of formaldehyde.

37 citations

Journal ArticleDOI
TL;DR: The significance of two-dimensional (2D) materials including graphene, and transition metal dichalcogenides has been escalating in gas sensor technology owing to detection of gases at room temperature (RT) and good performance as discussed by the authors .
Abstract: The significance of two-dimensional (2D) materials including graphene, and transition metal dichalcogenides has been escalating in gas sensor technology owing to detection of gases at room temperature (RT) and good...

1 citations

Journal ArticleDOI
TL;DR: In this paper , a research on the evaluation of adolescent lower limb posture correction based on collaborative filtering and microsensors is carried out, which simplifies the existing human body posture monitoring model and establishes a human body model with four degrees of freedom of the lower limbs.
Abstract: Automatic monitoring of physical activity provides reliable data support for the maintenance of people's physical health and provides more scientific data for studying the relationship between physical activity and disease. In this article, a research on the evaluation of adolescent lower limb posture correction based on collaborative filtering and microsensors is carried out. Aiming at the problem that the human body posture monitoring system needs multiple nodes, this article simplifies the existing human body posture monitoring model and establishes a human body model with four degrees of freedom of the lower limbs. On this basis, the micro-sensor assembly scheme and monitoring node layout scheme for obtaining model description parameters are determined. Methods such as collaborative filtering and support vector machines are used in the process of sensor data processing and correction effect evaluation. Finally, this article uses the constructed human body posture monitoring system to carry out the recognition test of the specific posture of the human body. The experimental results show that the evaluation scheme can effectively monitor and evaluate the effect of lower limb posture correction in adolescents.

1 citations

Journal ArticleDOI
TL;DR: In this article , density functional theory (DFT) analyzes the electronic structure of sensing materials and the adsorption energy of butyl acetate, and the effects of Ni element doping, oxygen vacancy constructions, and NiO quantum dot modifications on the modulation of the electronic structures of ZnO and on the ad-hoc energy of Butyl Acetate are investigated in detail.
References
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Journal ArticleDOI
TL;DR: In this article, a hierarchical NiO nanostructure sensing layer was used as highly sensitive formaldehyde sensor in the presence of light and the response was found to be 292% with a fast response of 24 s and recovery time of 42 s.
Abstract: Indoor air quality (IAQ) monitoring is essential to maintain healthy human life. Among different pollutants affecting IAQ, formaldehyde is one of the toxic volatile organic compounds (VOC) that needs to be monitored. In this paper, hierarchical NiO nanostructure sensing layer was used as highly sensitive formaldehyde sensor in the presence of light. The response was found to be 292% in the presence of 190 ppm formaldehyde with a fast response ~24 s and recovery ~42 s time. The sensor was found to be highly specific towards formaldehyde compared to other VOCs. The LOD calculated for the sensor was as low as 910 ppb. The optimum operating temperature was found to be ~300°C, much less than the conventional NiO-based sensors (~600°C). The sensing layer was found to be optically active due to the induced defects in the NiO nanostructure. Thus, the fabricated light-assisted sensor shows potential for future commercial formaldehyde sensor.

14 citations


"Fabrication of Microsensor for Dete..." refers background in this paper

  • ...gold acts as a catalyst for the metal oxide gas sensors [24]....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the design and fabrication of an ordered nanoporous silicon membrane and integrated heater and temperature sensor is described, and the methodology for fabrication of the nanoporous structure has been developed for integration within microelectromechanical systems.
Abstract: The design and fabrication of an ordered nanoporous silicon membrane and integrated heater and temperature sensor is described. The methodology for fabrication of the nanoporous structure has been developed for integration within microelectromechanical systems. The structure is fabricated from a 500 µm thick silicon (1 0 0) wafer, which has been etched to provide 4 × 4 mm2 membranes of 50 µm thick. Quasi-ordered nanoporous silicon is created within the membrane, the nanopores are of uniform diameter (typical structures of the order of 105 ±5 nm) and smooth sidewalls to a depth of ~300 nm, in a hexagonal close-packed pattern of 200 nm nearest neighbour. The porosity of typical fabricated samples is 31.5%. On the back side of the membrane, a heater and a temperature sensor are incorporated. Three different heater/temperature sensor designs were considered theoretically and the best design was then fabricated and studied experimentally. The results obtained provide both highly ordered nanoporous silicon fabrication methodology as well as evidence that the porous membrane can be heated without deleterious effect.

13 citations


"Fabrication of Microsensor for Dete..." refers background in this paper

  • ...4 × 10−3/◦C) in the wide temperature range [15]....

    [...]

  • ...Over the past few decades, various metals and nonmetals, such as platinum [14], gold [15], polysilicon [16], molybdenum [17], nichrome [18], and tungsten [19], are being used as a microheater material for the production of metal oxide gas sensors and are fabricated using conventional lithographybased microfabrication techniques....

    [...]

Journal ArticleDOI
TL;DR: The correlation between the location of temperature gradients and the positions where breakdown is observed on different Pt filament layouts in cantilever and full membrane type micro-hotplates is established and the temperature gradient driven thermomigration of Pt was identified.

11 citations


"Fabrication of Microsensor for Dete..." refers background in this paper

  • ...Over the past few decades, various metals and nonmetals, such as platinum [14], gold [15], polysilicon [16], molybdenum [17], nichrome [18], and tungsten [19], are being used as a microheater material for the production of metal oxide gas sensors and are fabricated using conventional lithographybased microfabrication techniques....

    [...]