scholarly journals Nanostructured ZnO/Ag Film Prepared by Magnetron Sputtering Method for Fast Response of Ammonia Gas Detection

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1899 ◽  
Author(s):  
Yiran Zheng ◽  
Min Li ◽  
Xiaoyan Wen ◽  
Ho-Pui Ho ◽  
Haifei Lu
Keyword(s):  
Magnetron Sputtering ◽  
Thermal Annealing ◽  
Physical Vapor Deposition ◽  
Gas Sensing ◽  
Volume Ratio ◽  
Fast Response ◽  
Gas Detection ◽  
Zno Films ◽  
Zno Film ◽  
Ammonia Gas

Possessing a large surface-to-volume ratio is significant to the sensitive gas detection of semiconductor nanostructures. Here, we propose a fast-response ammonia gas sensor based on porous nanostructured zinc oxide (ZnO) film, which is fabricated through physical vapor deposition and subsequent thermal annealing. In general, an extremely thin silver (Ag) layer (1, 3, 5 nm) and a 100 nm ZnO film are sequentially deposited on the SiO2/Si substrate by a magnetron sputtering method. The porous nanostructure of ZnO film is formed after thermal annealing contributed by the diffusion of Ag among ZnO crystal grains and the expansion of the ZnO film. Different thicknesses of the Ag layer help the formation of different sizes and quantities of hollows uniformly distributed in the ZnO film, which is demonstrated to hold superior gas sensing abilities than the compact ZnO film. The responses of the different porous ZnO films were also investigated in the ammonia concentration range of 10 to 300 ppm. Experimental results demonstrate that the ZnO/Ag(3 nm) sensor possesses a good electrical resistance variation of 85.74% after exposing the sample to 300 ppm ammonia gas for 310 s. Interestingly, a fast response of 61.18% in 60 s for 300 ppm ammonia gas has been achieved from the ZnO/Ag(5 nm) sensor, which costs only 6 s for the response increase to 10%. Therefore, this controllable, porous, nanostructured ZnO film maintaining a sensitive gas response, fabricated by the physical deposition approach, will be of great interest to the gas-sensing community.

scholarly journals High-Sensitive Numerical Gas Detection Using LSPR Effect and Fano Resonance in a Slotted MDM Structure

2021 ◽  
Author(s):  
Hai Liu ◽  
Benlei Zhao ◽  
Xu Zhang ◽  
Hancheng Zhang ◽  
Bo Wu ◽  
...  
Keyword(s):  
Fano Resonance ◽  
Gas Sensing ◽  
Field Enhancement ◽  
Fast Response ◽  
Gas Detection ◽  
Localized Surface Plasmon ◽  
Gas Sensitivity ◽  
Combined Use ◽  
Coherent Coupling ◽  
Lspr Effect

AbstractA high-sensitive numerical measurement of methane based on the combined use of the localized surface plasmon resonance (LSPR) and Fano resonance in a slotted metal-dielectric-metal (MDM) periodic structure is numerically investigated. A groove is etched in an original MDM structure to excite the diploe mode at both sides of the groove, and the coherent coupling of two dipole modes is enhanced to realize a fast response, which is beneficial to gas-sensing. The influence of geometric parameters on the reflection spectra and methane sensitivity are analyzed to obtain optimal geometry. Moreover, an etching ring is introduced on the top metal to further raise the coupling area and coupling strength. The Fano resonance is subtly integrated into the optimized structure with asymmetry to achieve greater gas sensitivity. After the introduction of the Fano resonance, the field enhancement caused by the LSPR effect becomes greater and the methane sensitivity can reach up to 8.421 nm/% in numerical calculations, which increases 56.8% more than that of the original one. The combined use of the LSPR and Fano resonance in an optimized MDM structure provides an effective method for high-sensitive gas detection.

scholarly journals Three-dimensional platinum nanoparticle-based bridges for ammonia gas sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nishchay A. Isaac ◽  
Johannes Reiprich ◽  
Leslie Schlag ◽  
Pedro H. O. Moreira ◽  
Mostafa Baloochi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Response Times ◽  
High Surface ◽  
Three Dimensional ◽  
Performance Testing ◽  
Volume Ratio ◽  
Platinum Nanoparticle ◽  
Ammonia Gas ◽  
Lift Off

AbstractThis study demonstrates the fabrication of self-aligning three-dimensional (3D) platinum bridges for ammonia gas sensing using gas-phase electrodeposition. This deposition scheme can guide charged nanoparticles to predetermined locations on a surface with sub-micrometer resolution. A shutter-free deposition is possible, preventing the use of additional steps for lift-off and improving material yield. This method uses a spark discharge-based platinum nanoparticle source in combination with sequentially biased surface electrodes and charged photoresist patterns on a glass substrate. In this way, the parallel growth of multiple sensing nodes, in this case 3D self-aligning nanoparticle-based bridges, is accomplished. An array containing 360 locally grown bridges made out of 5 nm platinum nanoparticles is fabricated. The high surface-to-volume ratio of the 3D bridge morphology enables fast response and room temperature operated sensing capabilities. The bridges are preconditioned for ~ 24 h in nitrogen gas before being used for performance testing, ensuring drift-free sensor performance. In this study, platinum bridges are demonstrated to detect ammonia (NH3) with concentrations between 1400 and 100 ppm. The sensing mechanism, response times, cross-sensitivity, selectivity, and sensor stability are discussed. The device showed a sensor response of ~ 4% at 100 ppm NH3 with a 70% response time of 8 min at room temperature.

scholarly journals A Review of Carbon Nanotubes-Based Gas Sensors

2009 ◽  
Vol 2009 ◽  
pp. 1-24 ◽  
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.

scholarly journals Ammonia Gas Detection by Tannic Acid Functionalized and Reduced Graphene Oxide at Room Temperature

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Sweejiang Yoo ◽  
Xin Li ◽  
Yuan Wu ◽  
Weihua Liu ◽  
Xiaoli Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Gas Sensor ◽  
Tannic Acid ◽  
Room Temperature ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Gas Detection ◽  
Ammonia Gas ◽  
Reduced Graphene

Reduced graphene oxide (rGO) based chemiresistor gas sensor has received much attention in gas sensing for high sensitivity, room temperature operation, and reversible. Here, for the first time, we present a promising chemiresistor for ammonia gas detection based on tannic acid (TA) functionalized and reduced graphene oxide (rGOTA functionalized). Green reductant of TA plays a major role in both reducing process and enhancing the gas sensing properties ofrGOTA functionalized. Our results showrGOTA functionalizedonly selective to ammonia with excellent respond, recovery, respond time, and recovery times.rGOTA functionalizedelectrical resistance decreases upon exposure to NH3where we postulated that it is due to n-doping by TA and charge transfer betweenrGOTA functionalizedand NH3through hydrogen bonding. Furthermore,rGOTA functionalizedhinders the needs for stimulus for both recovery and respond. The combination of greener sensing material and simplicity in overall sensor design provides a new sight for green reductant approach of rGO based chemiresistor gas sensor.

Influence of rapid thermal annealing on surface texture-etched Al-doped ZnO films prepared by various magnetron sputtering methods

2012 ◽  
Vol 520 (10) ◽  
pp. 3803-3807 ◽  
Author(s):  
Tadatsugu Minami ◽  
Tomoyasu Hirano ◽  
Toshihiro Miyata ◽  
Jun-ichi Nomoto
Keyword(s):  
Magnetron Sputtering ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Surface Texture ◽  
Zno Films ◽  
Doped Zno

Zinc Oxide Thin Films Grown on Nanostructured Al Thin Layer/Glass Substrate by RF Magnetron Sputtering

2011 ◽  
Vol 239-242 ◽  
pp. 777-780
Author(s):  
Ting Zhi Liu ◽  
Shu Wang Duo ◽  
C Y Hu ◽  
C B Li
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Magnetron Sputtering ◽  
Thin Layer ◽  
Glass Substrate ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
Zno Film ◽  
Substrate Roughness ◽  
Axis Orientation

ZnO films were deposited on nanostructured Al (n-Al) /glass substrate by RF magnetron sputtering. The results shows that the relation (I (002) /I (100) ≈ I annealed (002)/I annealed (100) ≈1.1) shows the rough n-Al surface is suitable for the growth of a-axis orientation. Meanwhile, the influences of substrate roughness, crystallinity and (101) plane of ZnO film deposited on n-Al layer have been discussed. XPS implies more oxygen atoms are bound to Aluminum atoms, which result in the increase of high metallic Zn in the film.

Properties of Nano-ZnO Films Deposited by RF Magnetron Sputtering for SAW Biosensors

2011 ◽  
Vol 418-420 ◽  
pp. 293-296
Author(s):  
Qiu Yun Fu ◽  
Peng Cheng Yi ◽  
Dong Xiang Zhou ◽  
Wei Luo ◽  
Jian Feng Deng
Keyword(s):  
Magnetron Sputtering ◽  
Deposition Time ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Nano Zno ◽  
Axis Orientation ◽  
X Ray

Abstract. In this article, nano-ZnO films were deposited on SiO2/Si (100) substrates by RF (radio frequency) magnetron sputtering using high purity (99.99%) ZnO target. The effects of deposition time and annealing temperature have been investigated. XRD (X-ray diffraction) and FSEM (Field Emission Scanning Electron Microscopy) were employed to characterize the quality of the films. The results show that the ZnO film with thickness of 600nm annealed at 900°C has higher quality of both C-axis orientation and crystallization. And for the Zone film with thickness of 300nm annealed at 850°C, the quality of both C-axis orientation and crystallization is higher than that annealed at 900°C and 950°C.

Effect of Thermal Annealing on Ga-Doped ZnO Films Prepared by Magnetron Sputtering

2007 ◽  
Vol 154 (6) ◽  
pp. H521 ◽  
Author(s):  
J. K. Sheu ◽  
K. W. Shu ◽  
M. L. Lee ◽  
C. J. Tun ◽  
G. C. Chi
Keyword(s):  
Magnetron Sputtering ◽  
Thermal Annealing ◽  
Zno Films ◽  
Doped Zno

Structural color and photocatalytic property of polyester fabrics coated with Ag/ZnO composite films

2019 ◽  
Vol 31 (4) ◽  
pp. 487-494 ◽  
Author(s):  
Xiaohong Yuan ◽  
Qufu Wei ◽  
Huizhen Ke ◽  
Zujian Huang ◽  
Dongsheng Chen
Keyword(s):  
Zinc Oxide ◽  
Magnetron Sputtering ◽  
Composite Films ◽  
Photocatalytic Property ◽  
Zno Films ◽  
Zno Film ◽  
Polyester Fabrics ◽  
Content Type ◽  
Structural Colors ◽  
The Relationship

Purpose The purpose of this paper is to prepare structural colors of fabrics coated with Silver/Zinc Oxide (Ag/ZnO) composite films by magnetron sputtering and analyze the relationship between the colors and the thickness of Zinc Oxide (ZnO) film in Ag/ZnO composite film and the photocatalytic property of the fabrics coated with Ag/ZnO composite film. Design/methodology/approach Ag/ZnO composite films deposited on polyester fabrics were prepared by magnetron sputtering technology. The structural colors of textiles coated with Ag/ZnO composite films and the relationship between the colors and Ag/ZnO composite films were analyzed, and the photocatalytic property of Ag/ZnO composite films was also discussed. Findings The results indicated that the colors varied with the thicknesses of the ZnO film in Ag/ZnO composite films. The reactive sputtering time of ZnO film was 5, 8, 10 and 14 min, respectively, and the colors of the corresponding fabrics were purple, blue, blue-green and yellow. Meanwhile, the polyester fabrics coated with Ag/ZnO composite films showed the excellent photocatalytic properties, and silver (Ag) films deposited under the ZnO films in Ag/ZnO composite films could also improve the photocatalytic activities of ZnO films, and the formaldehyde degradation rates was 77.5%, which was higher than the 69.9% for the fabrics coated only with the ZnO film. Originality/value The polyester fabrics coated with Ag/ZnO composite films not only created various structural colors using change the thicknesses of the ZnO film, but also achieved the multifuctionality, which will have a broad application prospect in textile fields.

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