scholarly journals CuO Thin Films Functionalized with Gold Nanoparticles for Conductometric Carbon Dioxide Gas Sensing

Chemosensors ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 56 ◽  
Author(s):  
Robert Wimmer-Teubenbacher ◽  
Florentyna Sosada-Ludwikowska ◽  
Bernat Travieso ◽  
Stefan Defregger ◽  
Oeznur Tokmak ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Carbon Dioxide ◽  
Gold Nanoparticles ◽  
Gas Sensors ◽  
Mass Production ◽  
Gas Sensing ◽  
Cupric Oxide ◽  
Base Material ◽  
Lift Off

Metal oxides (MOx) are a well-established material for gas sensing. MOx-based gas sensors are sensitive to a wide variety of gases. Furthermore, these materials can be applied for the fabrication of low-cost and -power consumption devices in mass production. The market of carbon dioxide (CO 2 ) gas sensors is mainly dominated by infra-red (IR)-based gas sensors. Only a few MOx materials show a sensitivity to CO 2 and so far, none of these materials have been integrated on CMOS platforms suitable for mass production. In this work, we report a cupric oxide (CuO) thin film-based gas sensor functionalized with gold (Au) nanoparticles, which exhibits exceptional sensitivity to CO 2 . The CuO-based gas sensors are fabricated by electron beam lithography, thermal evaporation and lift-off process to form patterned copper (Cu) structures. These structures are thermally oxidized to form a continuous CuO film. Gold nanoparticles are drop-coated on the CuO thin films to enhance their sensitivity towards CO 2 . The CuO thin films fabricated by this method are already sensitive to CO 2 ; however, the functionalization of the CuO film strongly increases the sensitivity of the base material. Compared to the pristine CuO thin film the Au functionalized CuO film shows at equal operation temperatures (300 ∘ C) an increase of sensitivity towards the same gas concentration (e.g., 2000 ppm CO 2 ) by a factor of 13. The process flow used to fabricate Au functionalized CuO gas sensors can be applied on CMOS platforms in specific post processing steps.

scholarly journals Nanostructured Materials Based on Thin Films and Nanoclusters for Hydrogen Gas Sensing

Proceedings ◽  
2021 ◽  
Vol 56 (1) ◽  
pp. 38
Author(s):  
Stanislav Haviar ◽  
Nirmal Kumar ◽  
Šárka Batková ◽  
Jiří Čapek
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
Tungsten Trioxide ◽  
Gas Sensing ◽  
Cupric Oxide ◽  
Hydrogen Gas ◽  
Oxide Semiconductors ◽  
Copper Tungstate ◽  
Solid Film ◽  
Nanostructured Metal

In this paper, we present two approaches to synthesize nanostructured metal oxide semiconductors in a form of multi-layer thin films later assembled as a conductometric gas-sensors. The first approach produces a combination of thin solid film of tungsten trioxide (WO3) with nanoclusters of cupric oxide (CuO) prepared by a magnetron-based gas aggregation cluster source (GAS). The second method is a two-step reactive magnetron sputtering forming a nanostructured copper tungstate (CuWO4) on-top of a WO3 film. Both methods lead to synthesis of nanosized hetero-junctions. These greatly improve the sensorial response to hydrogen in comparison with a WO3 thin film alone.

Sputtered Nickel Oxide Films for NO2 Gas Sensors

2013 ◽  
Vol 678 ◽  
pp. 361-364 ◽  
Author(s):  
Avula Mallikarjuna Reddy ◽  
Akepati Sivasankar Reddy ◽  
Pamanji Sreedhara Reddy
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Nickel Oxide ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Oxide Thin Film ◽  
Nickel Metal ◽  
Force Microscopy ◽  
Nio Thin Film

In recent years, lot of efforts was made to develop many types of nitrogen oxide gas sensors. Among them, most interesting are WO3, V2O5, TiO2, SnO2 and NiO thin films as gas sensing layers. Relatively small effort has been done to examine nickel oxide. But reasonably good electrical properties and stability in air make it feasible for the fabrication of nickel oxide thin film based gas sensors. Hence, in the present study NiO thin films were deposited by dc reactive magnetron sputtering technique from a nickel metal target in argon and oxygen mixed atmosphere and studied its gas sensing properties towards NO2 gas. The effect of process parameters on the morphological and electrical properties of NiO was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Hall effect studies respectively. The films prepared at optimum conditions showed superior electrical properties and exhibited fine and uniform grains with RMS roughness 9.4 nm. These films were tested for gas sensing characteristics of NO2 gas. The sensitivity of NiO thin film was investigated in the temperature range 373 to 573 K. The dynamic response for the NiO films was observed at an operating temperature of 473 K and gas concentration of 50 ppm for NO2 gas.

scholarly journals On the Use of MOFs and ALD Layers as Nanomembranes for the Enhancement of Gas Sensors Selectivity

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1552 ◽  
Author(s):  
Weber ◽  
Graniel ◽  
Balme ◽  
Miele ◽  
Bechelany
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Metal Organic Frameworks ◽  
Atomic Layer ◽  
Operational Performance ◽  
Layer Deposition ◽  
Metal Organic ◽  
Further Development ◽  
Different Gases

Improving the selectivity of gas sensors is crucial for their further development. One effective route to enhance this key property of sensors is the use of selective nanomembrane materials. This work aims to present how metal-organic frameworks (MOFs) and thin films prepared by atomic layer deposition (ALD) can be applied as nanomembranes to separate different gases, and hence improve the selectivity of gas sensing devices. First, the fundamentals of the mechanisms and configuration of gas sensors will be given. A selected list of studies will then be presented to illustrate how MOFs and ALD materials can be implemented as nanomembranes and how they can be implemented to improve the operational performance of gas sensing devices. This review comprehensively shows the benefits of these novel selective nanomaterials and opens prospects for the sensing community.

Effect of Temperature on the Electrical and Gas Sensing Properties of Polyaniline and Multiwall Carbon Nanotube Doped Polyaniline Composite Thin Films

2011 ◽  
Vol 254 ◽  
pp. 167-170 ◽  
Author(s):  
Subodh Srivastava ◽  
Sumit Kumar ◽  
Vipin Kumar Jain ◽  
Y.K. Vijay
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Gas Sensing ◽  
Hydrogen Gas ◽  
Composite Thin Film ◽  
Effect Of Temperature ◽  
Multiwall Carbon Nanotube ◽  
Film Sensor ◽  
Composite Thin Films ◽  
Pani Composite

In the present work we have reported the effect of temperature on the gas sensing properties of pure Polyaniline (PANI) and Multiwall carbon nanotube (MWNT) doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and MWNT doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline using ammonium persulfate in an acidic medium. The thin sensing film of chemically synthesized PANI and MWNT doped PANI composite were deposited onto finger type Cu-interdigited electrodes using spin cast technique to prepared chemiresistor type gas sensor. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature, MWNT doped PANI composite sensor shows higher response value and sensitivity with good repeatability in comparison to pure PANI thin film sensor. It was also observed that both PANI and MWNT doped PANI composite thin film based sensors showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement.

Epitaxial growth of β-Ga2O3 (-201) thin film on fourfold symmetry CeO2 (001) substrate for heterogeneous integrations

2021 ◽  
Author(s):  
Xiao Tang ◽  
Kuanghui Li ◽  
Che-Hao Liao ◽  
Dongxing Zheng ◽  
chen Liu ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Epitaxial Growth ◽  
Gas Sensors ◽  
High Power ◽  
Wide Bandgap ◽  
Semiconductor Material ◽  
Uv Detectors ◽  
Wide Bandgap Semiconductor ◽  
Fourfold Symmetry

β-Ga2O3 is a wide bandgap semiconductor material promising for many fields such as gas sensors, UV detectors, and high power electronics. Until now, most epitaxial β-Ga2O3 thin films could only...

scholarly journals A tunable volatile organic compound sensor by using PtOx/GQDs/TiO2 nanocomposite thin films at room temperature under visible-light activation

RSC Advances ◽  
2017 ◽  
Vol 7 (63) ◽  
pp. 39859-39868 ◽  
Author(s):  
Shaofeng Shao ◽  
Yunyun Chen ◽  
Shenbei Huang ◽  
Fan Jiang ◽  
Yunfei Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Visible Light ◽  
Gas Sensors ◽  
Room Temperature ◽  
Light Activation ◽  
Nanocomposite Thin Film ◽  
Nanocomposite Thin Films ◽  
Volatile Organic ◽  
Visible Light Activation

Pt/GQDs/TiO2 nanocomposite thin film-based gas sensors show tunable VOC sensing behaviour at room temperature under visible-light activation.

Mass Production and Film Thickness Control of Meso Porous Silica Thin Films

2020 ◽  
Author(s):  
Makio Tamada ◽  
Yuta Sunami
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Film Thickness ◽  
Mass Production ◽  
Porous Silica ◽  
Production Method ◽  
Liquid Pool ◽  
Speed Ratio ◽  
Roll To Roll ◽  
New Material

Abstract Mesoporous silica (referred to as MPS), which has pores of hexagonal or cubic structure of several nm to several tens of nm on the surface, is attracting attention as a new material. MPS has a very large specific surface area, so it is used as an adsorbent for gas and water vapor, as a moisture absorbent, and as a separating material. Transparent MPS is also expected to be an optical functional material. MPS thin film is expected to be used as a thin film as an application example. Since MPS thin film can be used in various applications, it will be further developed by mass production. Leads to Therefore, in this study, mass production of MPS thin films and controlled the film thickness was studied. Roll-to-roll (referred to as R2R) production method and a micro gravure printing method was adopted as a method of mass production: transporting polypropylene film and coating on it. As a result, the MPS thin film prepared in this study had a pore structure. it was confirmed that the film thickness could be controlled by changing the peripheral speed ratio. It is considered that the size of the liquid pool between the coating rolls changed. The size and arrangement of the pores could be confirmed by FE-SEM observation.

The Controllable Flexible Features of ZnO Thin Film Gas Sensor

2011 ◽  
Vol 335-336 ◽  
pp. 478-482 ◽  
Author(s):  
Xin Liang Cao
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Zno Thin Film ◽  
Preparation Methods

For different gas sensing, the preparation of Zinc Oxide (ZnO) thin film gas sensor has its particularity. In this paper, three kinds of preparation methods, fitting for CO and methane and CO2 sensing, are introduced. Moreover, the sensitivity is respectively analyzed as gas sensors. The reference is provided for the preparation and applications of ZnO thin film gas sensor.

Performance of Low Resistivity Electrode Prepared by Electroless Plated for Amorphous Silicon Thin-Film Transistors

2007 ◽  
Vol 561-565 ◽  
pp. 1165-1168 ◽  
Author(s):  
Chien Yie Tsay ◽  
Chung Kwei Lin ◽  
Hong Ming Lin ◽  
Shih Chieh Chang ◽  
Bor Chuan Chung
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Amorphous Silicon ◽  
Large Area ◽  
Silicon Thin Film ◽  
Adhesion Properties ◽  
Low Resistivity ◽  
N2 Atmosphere ◽  
Lift Off ◽  
Processing Steps

The TFTs array fabrication process for large-area TFT-LCD has been continuously developed for simplifying processing steps, improving performance and reducing cost in the process of mass production. In this study, the hydrogenated amorphous silicon (a-Si:H) TFTs with low resistivity electrodes , silver thin films, were prepared by using the selective deposition method that combined lift-off and electroless plated processes. This developed process can direct pattern the electrode of transistor devices without the etching process and provide ease processing steps. The as-deposited Ag films were annealed at 200 oC for 10 minutes under N2 atmosphere. The results shows that the adhesion properties can be enhanced and the resistivity has been improved from 6.0 μ,-cm, significantly decrease by 35%, of as-deposited Ag films by annealed. The thickness of Ag thin film is about 100 nm and the r. m. s roughness value is 1.54 nm. The a-Si:H TFT with Ag thin films as source and drain electrodes had a field effect mobility of 0.18 cm2/Vs, a threshold voltage of 2.65 V, and an on/off ratio of 3×104.

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