scholarly journals Tuning Stoichiometry and Structure of Pd-WO3−x Thin Films for Hydrogen Gas Sensing by High-Power Impulse Magnetron Sputtering

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5101
Author(s):  
Nirmal Kumar ◽  
Stanislav Haviar ◽  
Jiří Rezek ◽  
Pavel Baroch ◽  
Petr Zeman
Keyword(s):  
Magnetron Sputtering ◽  
High Power ◽  
Gas Sensing ◽  
Pulse Length ◽  
Pd Nanoparticles ◽  
Hydrogen Gas ◽  
Sensory Response ◽  
Hydrogen Sensing ◽  
Sensing Applications ◽  
Deposition Parameters

By tuning the deposition parameters of reactive high-power impulse magnetron sputtering, specifically the pulse length, we were able to prepare WO3−x films with various stoichiometry and structure. Subsequently, the films were annealed in air at moderate temperature (350 °C). We demonstrate that the stoichiometry of the as-deposited films influences considerably the type of crystalline phase formed in the annealed films. The appropriate sub-stoichiometry of the films (approx. WO2.76) enabled crystallization of the monoclinic phase during the annealing. This phase is favorable for hydrogen sensing applications. To characterize the sensory behavior of the films, the tungsten oxide films were decorated by Pd nanoparticles before annealing and were assembled as a conductometric gas sensor. The sensory response of the films that crystallized in the monoclinic structure was proven to be superior to that of the films containing other phases.

scholarly journals Transforming Pt-SnO2 Nanoparticles into Pt-SnO2 Composite Nanoceramics for Room-Temperature Hydrogen-Sensing Applications

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2123
Author(s):  
Ming Liu ◽  
Caochuang Wang ◽  
Pengcheng Li ◽  
Liang Cheng ◽  
Yongming Hu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Sintering Temperature ◽  
Sno2 Nanoparticles ◽  
Hydrogen Sensing ◽  
Sensing Applications ◽  
Nanostructured Metal Oxides ◽  
Low Dimensional ◽  
Sensing Characteristics ◽  
Nanostructured Metal

Many low-dimensional nanostructured metal oxides (MOXs) with impressive room-temperature gas-sensing characteristics have been synthesized, yet transforming them into relatively robust bulk materials has been quite neglected. Pt-decorated SnO2 nanoparticles with 0.25–2.5 wt% Pt were prepared, and highly attractive room-temperature hydrogen-sensing characteristics were observed for them all through pressing them into pellets. Some pressed pellets were further sintered over a wide temperature range of 600–1200 °C. Though the room-temperature hydrogen-sensing characteristics were greatly degraded in many samples after sintering, those samples with 0.25 wt% Pt and sintered at 800 °C exhibited impressive room-temperature hydrogen-sensing characteristics comparable to those of their counterparts of as-pressed pellets. The variation of room-temperature hydrogen-sensing characteristics among the samples was explained by the facts that the connectivity between SnO2 grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO2 at high temperatures. These results clearly demonstrate that some low-dimensional MOX nanocrystals can be successfully transformed into bulk MOXs with improved robustness and comparable room-temperature gas-sensing characteristics.

scholarly journals Developing GLAD Parameters to Control the Deposition of Nanostructured Thin Film

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 651
Author(s):  
Jakub Bronicki ◽  
Dominik Grochala ◽  
Artur Rydosz
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Glancing Angle Deposition ◽  
Metal Oxide Thin Films ◽  
Nanostructured Thin Film ◽  
Sensing Applications ◽  
Deposition Parameters ◽  
Glancing Angle ◽  
Glad Technique ◽  
Relative Errors

In this paper, we describe the device developed to control the deposition parameters to manage the glancing angle deposition (GLAD) process of metal-oxide thin films for gas-sensing applications. The GLAD technique is based on a set of parameters such as the tilt, rotation, and substrate temperature. All parameters are crucial to control the deposition of nanostructured thin films. Therefore, the developed GLAD controller enables the control of all parameters by the scientist during the deposition. Additionally, commercially available vacuum components were used, including a three-axis manipulator. High-precision readings were tested, where the relative errors calculated using the parameters provided by the manufacturer were 1.5% and 1.9% for left and right directions, respectively. However, thanks to the formula developed by our team, the values were decreased to 0.8% and 0.69%, respectively.

The Influence of Pulse Width on Microstructure and Mechanical Properties of CrNx Coatings Deposited by HPPMS

2014 ◽  
Vol 633 ◽  
pp. 398-401
Author(s):  
Xiang Min Xu ◽  
Hao Zhang ◽  
Yi Bin Jin ◽  
Hao Chen Zhao ◽  
Shu Wang Duo
Keyword(s):  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
High Power ◽  
Pulse Width ◽  
Pulse Length ◽  
Closed Field ◽  
Power Pulse ◽  
Phase Structures ◽  
Microstructure And Mechanical Properties ◽  
High Power Pulse

CrNx coatings were deposited by high power pulse magnetron sputtering in a closed field unbalanced system. The influence of pulse width on microstructure and mechanical properties of CrNx coatings was examined. Morphologies different from those fabricated by traditional magnetron sputtering were obtained, phase structures were also changed in the process. The coatings hardness were always improved in the increasing pulse length, while the best adhension of CrNx coatings about 25N was get when pulse length was 60us.

scholarly journals Three-Layer PdO/CuWO4/CuO System for Hydrogen Gas Sensing with Reduced Humidity Interference

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3456
Author(s):  
Nirmal Kumar ◽  
Stanislav Haviar ◽  
Petr Zeman
Keyword(s):  
Gas Sensing ◽  
Cupric Oxide ◽  
Hydrogen Gas ◽  
Base Layer ◽  
Layer System ◽  
Seamless Integration ◽  
Hydrogen Sensing ◽  
Reactive Sputter Deposition ◽  
Copper Tungstate ◽  
Higher Sensitivity

The growing hydrogen industry is stimulating an ongoing search for new materials not only for hydrogen production or storage but also for hydrogen sensing. These materials have to be sensitive to hydrogen, but additionally, their synthesis should be compatible with the microcircuit industry to enable seamless integration into various devices. In addition, the interference of air humidity remains an issue for hydrogen sensing materials. We approach these challenges using conventional reactive sputter deposition. Using three consequential processes, we synthesized multilayer structures. A basic two-layer system composed of a base layer of cupric oxide (CuO) overlayered with a nanostructured copper tungstate (CuWO4) exhibits higher sensitivity than individual materials. This is explained by the formation of microscopic heterojunctions. The addition of a third layer of palladium oxide (PdO) in forms of thin film and particles resulted in a reduction in humidity interference. As a result, a sensing three-layer system working at 150 °C with an equalized response in dry/humid air was developed.

Optimizing the deposition rate and ionized flux fraction by tuning the pulse length in high power impulse magnetron sputtering

2020 ◽  
Vol 29 (5) ◽  
pp. 05LT01 ◽  
Author(s):  
Martin Rudolph ◽  
Nils Brenning ◽  
Michael A. Raadu ◽  
Hamidreza Hajihoseini ◽  
Jon Tomas Gudmundsson ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Deposition Rate ◽  
High Power ◽  
Pulse Length

Structure of Hydrogen Gas Sensing TiO2 Thin Films Prepared by Sol-Gel Method and their Comparison with Magnetron Sputtered Films

2013 ◽  
Vol 543 ◽  
pp. 293-296 ◽  
Author(s):  
G. Plesch ◽  
A.A. Haidry ◽  
M. Gregor ◽  
P. Durina ◽  
J. Gregus ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Gas Sensing ◽  
Sol Gel ◽  
Rutile Phase ◽  
Hydrogen Gas ◽  
Gel Method ◽  
Sensing Properties ◽  
Sol Gel Method ◽  
Coating Method

TiO2thin films with a thickness of about 150 nm were deposited by spin coating method on sapphire substrate from a sol-gel system. The hydrogen sensing properties of TiO2films annealed at various temperatures were studied and correlated with their structure, optical and electrical properties. The annealing temperatures in the range of 600 800 °C lead to anatase films with a roughness in the range of 0.6 0.9 nm. Their sensitivity towards hydrogen is low. The thin films annealed at temperatures in the range 900 1000 °C consist of rutile phase and their roughness increased to 11.7 13.5 nm. They showed good hydrogen sensitivity with optimal operating temperature 200 250 °C. The structure and sensing properties of the prepared films are compared with those synthesized with magnetron sputtering. The maximum of sensitivity was measured on the thin films with diameter of the grains about 100 nm in both cases, i.e. on thin films prepared by sol-gel method as well as on thin films prepared by magnetron sputtering. The maximum sensitivity correlates with the diameter of the grains and dont depend on the allotropy of the titanium dioxide anatase or rutile.

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