High Sensitivity Hybrid Plasmonic Rectangular Resonator for Gas Sensing Applications

2015 ◽  
Author(s):  
Aya O. Zaki ◽  
K. Kirah ◽  
Mohamed A. Swillam
Keyword(s):  
Gas Sensing ◽  
High Sensitivity ◽  
Sensing Applications

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.

SYNTHESIS AND MANIPULATION OF WO3 NANO PARTICLES FOR GAS SENSING APPLICATIONS

2012 ◽  
Vol 05 ◽  
pp. 227-233
Author(s):  
Elham kamali Heidari ◽  
Seyed Reza Mahmoodi ◽  
Ehsan Marzbanrad ◽  
Babak Raisi ◽  
Cyrus Zmani
Keyword(s):  
Gas Sensing ◽  
Average Particle Size ◽  
High Sensitivity ◽  
Nano Particles ◽  
Average Particle ◽  
Monoclinic Structure ◽  
Template Removal ◽  
Sensing Applications ◽  
Low Concentrations ◽  
Nanocasting Route

Ultra fine WO 3 nanoparticles were synthesized by nanocasting route, using mesoporous SiO 2 as a template. BET measurements showed a specific surface area of 700m2/gr for synthesized SiO 2 while after impregnation and template removal, this area was reduced to 43m2/gr for WO 3 nanoparticles. HRTEM results showed single crystalline nanoparticles with average particle size of about 5nm possessing a monoclinic structure which is the favorite crystal structure for gas sensing applications. Alternative electric field was applied to align synthesized WO 3 nanoparticles between electrodes. Gas sensing measurements showed that this material has a high sensitivity to very low concentrations of NO 2 at 250°C.

scholarly journals The Effect of CH4 and CO2 Exposure on Carbon Nanotubes Electrical Resistance

2011 ◽  
Vol 214 ◽  
pp. 655-661 ◽  
Author(s):  
Amin Firouzi ◽  
Shafreeza Sobri ◽  
Faizah Mohd Yasin ◽  
Fakhru'l Razi Ahmadun
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Resistance ◽  
Gas Sensing ◽  
Quartz Substrate ◽  
Chemical Vapor ◽  
High Sensitivity ◽  
Sensing Applications ◽  
Type Semiconductor ◽  
Adsorption Of Co2 ◽  
P Type

This research was carried out to monitor and investigate the gas sensing effects on carbon nanotubes (CNTs) by a systematic study of the variations in the electrical resistance as sensor signal induced by adsorption of CO2 and CH4 gaseous molecules. The CNTs were synthesized by Floating Catalyst Chemical Vapor Deposition (FC-CVD) method on quartz substrate under benzene bubble at temperature of 700°C. Then, they were tested for gas sensing applications operating at room temperature. Upon exposure to gaseous molecules, the electrical resistance of CNTs dramatically increased for both CO2 and CH4 gases with short response time and high sensitivity. It was also observed that the CNTs device behaves as a p-type semiconductor when exposed to gaseous molecules. In addition, the recovery of the sensors and mechanism of gas sensing procedure are discussed.

scholarly journals Tunable Infrared Metamaterial Emitter for Gas Sensing Application

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1442 ◽  
Author(s):  
Ruijia Xu ◽  
Yu-Sheng Lin
Keyword(s):  
High Efficiency ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Ir Radiation ◽  
Optical Efficiency ◽  
Sensing Applications ◽  
On Chip ◽  
Ir Emission

We present an on-chip tunable infrared (IR) metamaterial emitter for gas sensing applications. The proposed emitter exhibits high electrical-thermal-optical efficiency, which can be realized by the integration of microelectromechanical system (MEMS) microheaters and IR metamaterials. According to the blackbody radiation law, high-efficiency IR radiation can be generated by driving a Direct Current (DC) bias voltage on a microheater. The MEMS microheater has a Peano-shaped microstructure, which exhibits great heating uniformity and high energy conversion efficiency. The implantation of a top metamaterial layer can narrow the bandwidth of the radiation spectrum from the microheater to perform wavelength-selective and narrow-band IR emission. A linear relationship between emission wavelengths and deformation ratios provides an effective approach to meet the requirement at different IR wavelengths by tailoring the suitable metamaterial pattern. The maximum radiated power of the proposed IR emitter is 85.0 µW. Furthermore, a tunable emission is achieved at a wavelength around 2.44 µm with a full-width at half-maximum of 0.38 µm, which is suitable for high-sensitivity gas sensing applications. This work provides a strategy for electro-thermal-optical devices to be used as sensors, emitters, and switches in the IR wavelength range.

scholarly journals Silicon Microcantilever Sensors to Detect the Reversible Conformational Change of a Molecular Switch, Spiropyan

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 854 ◽  
Author(s):  
Catherine Grogan ◽  
George Amarandei ◽  
Shauna Lawless ◽  
Fran Pedreschi ◽  
Fiona Lyng ◽  
...  
Keyword(s):  
Conformational Change ◽  
Conformational Changes ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Molecular Switch ◽  
Medical Applications ◽  
Microcantilever Sensors ◽  
Sensing Applications ◽  
Reverse Transition ◽  
Photochromic Molecules

The high sensitivity of silicon microcantilever sensors has expanded their use in areas ranging from gas sensing to bio-medical applications. Photochromic molecules also represent promising candidates for a large variety of sensing applications. In this work, the operating principles of these two sensing methods are combined in order to detect the reversible conformational change of a molecular switch, spiropyran. Thus, arrays of silicon microcantilever sensors were functionalized with spiropyran on the gold covered side and used as test microcantilevers. The microcantilever deflection response was observed, in five sequential cycles, as the transition from the spiropyran (SP) (CLOSED) to the merocyanine (MC) (OPEN) state and vice-versa when induced by UV and white light LED sources, respectively, proving the reversibility capabilities of this type of sensor. The microcantilever deflection direction was observed to be in one direction when changing to the MC state and in the opposite direction when changing back to the SP state. A tensile stress was induced in the microcantilever when the SP to MC transition took place, while a compressive stress was observed for the reverse transition. These different type of stresses are believed to be related to the spatial conformational changes induced in the photochromic molecule upon photo-isomerisation.

scholarly journals Synthesis and characterization of silver oxide nanoparticles prepared by chemical bath deposition for NH3 gas sensing applications

2020 ◽  
pp. 772-779
Author(s):  
Hajar H. Nayel ◽  
Hamid S. AL-Jumaili
Keyword(s):  
Thin Films ◽  
Chemical Bath Deposition ◽  
Silver Oxide ◽  
Energy Gap ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Average Crystallite Size ◽  
Xrd Analysis ◽  
Oxide Thin Film ◽  
Sensing Applications

Nano-silver oxide thin films with high sensitivity for NH3 gas were deposited on glass substrates by the chemical bath deposition technique. The preparations were made under different values of pH and deposition time at 70ᵒ C, using silver nitrate AgNO3 and triethanolamine. XRD analysis showed that all thin films werepolycrystalline with several peaks of silver oxides such as Ag2O, AgO and Ag3O4, with an average crystallite size that ranged between 31.7 nm and 45.8 nm, depending on the deposition parameters. Atomic force microscope (AFM) technique illustrated that the films were homogenous with different surface roughness and thegrain size ranged between 55.69 nm and 86.23 nm. The UV-Vis spectrophotometer showed that the optical direct energy gap ranged between 1.66 eV to 2.12 eV. The silver oxide thin film gives a high sensitivity of 70.12 for NH3 gas at 75°C operating temperature. This study shows that different types of silver oxides can beprepared by the CBD techniques, with the nanostructure to be used in gas sensors and optoelectronic applications. 

PCB Mounted Sensor with High Sensitivity SWNT-Based Devices for Gas Sensing Applications

2021 ◽  
pp. 105043
Author(s):  
Narendra Kumar ◽  
Naveen Kumar Navani ◽  
Sanjeev Kumar Manhas
Keyword(s):  
Gas Sensing ◽  
High Sensitivity ◽  
Sensing Applications

Synthesis and characterization of ZnS-based quantum dots to trace low concentration of ammonia

2021 ◽  
Vol 42 (12) ◽  
pp. 122901
Author(s):  
Uma Devi Godavarti ◽  
P. Nagaraju ◽  
Vijayakumar Yelsani ◽  
Yamuna Pushukuri ◽  
P. S. Reddy ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Average Crystallite Size ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
Zinc Blend ◽  
Ammonia Sensing ◽  
Sensing Applications ◽  
Co Precipitation

Abstract In the present work, a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD, SEM, TEM with EDX, FTIR and gas sensing properties. XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure. TEM and XRD line broadening indicated that the average crystallite size in the sample is in the range of 2 to 5 nm. SEM micrographs show spherical-shaped quantum dots. FTIR studies show that cobalt has been successfully doped into the ZnS cubic lattice. EDX spectra have analyzed the elemental presence in the samples and it is evident that the spectra confirmed the presence of cobalt (Co), zinc (Zn), oxygen (O), and sulphur (S) elements only and no other impurities are observed. The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70 °C. Hence, ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.

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.

Effect of Grain Size on Strain in a Copper Oxide Nanofilm for Gas Sensing Applications

2019 ◽  
Vol 11 (5) ◽  
pp. 05040-1-05040-4
Author(s):  
Sumanta Kumar Tripathy ◽  
◽  
Sanjay Kumar ◽  
Divya Aparna Narava ◽  
◽  
...  
Keyword(s):  
Grain Size ◽  
Copper Oxide ◽  
Gas Sensing ◽  
Sensing Applications
Sign in / Sign up

Export Citation Format

Share Document