microwave plasma
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Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 626
Author(s):  
Seokhun Kwon ◽  
Seokwon Lee ◽  
Joouk Kim ◽  
Chulmin Park ◽  
Hosung Jung ◽  
...  

Recently, as air pollution and particulate matter worsen, the importance of a platform that can monitor the air environment is emerging. Especially, among air pollutants, nitrogen dioxide (NO2) is a toxic gas that can not only generate secondary particulate matter, but can also derive numerous toxic gases. To detect such NO2 gas at low concentration, we fabricated a GNWs/NiO-WO3/GNWs heterostructure-based gas sensor using microwave plasma-enhanced chemical vapor deposition (MPECVD) and sputter, and we confirmed the NO2 detection characteristics between 10 and 50 ppm at room temperature. The morphology and carbon lattice characteristics of the sensing layer were investigated using field emission scanning electron microscopy (FESEM) and Raman spectroscopy. In the gas detection measurement, the resistance negative change according to the NO2 gas concentration was recorded. Moreover, it reacted even at low concentrations such as 5–7 ppm, and showed excellent recovery characteristics of more than 98%. Furthermore, it also showed a change in which the reactivity decreased with respect to humidity of 33% and 66%.


Author(s):  
Shuya ASADA ◽  
Akihisa OGINO

Abstract The aim of this study is to form the sulfur defects on monolayer molybdenum disulfide (MoS2) by low temperature microwave plasma treatment suppressing disturbance of molecular structure. CVD-grown and plasma treated multilayer MoS2 surface were analyzed to investigate the effects of H2 and Ar plasma treatment on sulfur defects and molecular structure. It was found that the disturbance of molecular structure was suppressed in the H2 plasma treatment compared to the Ar plasma treatment. Varying the incident ratio of hydrogen ions H+ and radicals H*, the influences of H2 plasma treatment with high and low H*/H+ ratio on monolayer MoS2 structure were discussed. As a result of X-ray photoelectron spectroscopy, Raman spectroscopy and photoluminescence analysis, sulfur defects increased with the increase in total amount of radical incident on MoS2. In addition, it is speculated that the etching with radical contributed to form sulfur defects suppressing the disturbance of molecular structure.


2022 ◽  
Author(s):  
Justas Zalieckas ◽  
Ivan Rios Mondragon ◽  
Paulius Pobedinskas ◽  
Arne Skodvin Kristoffersen ◽  
Samih Mohamed-Ahmed ◽  
...  

Polycrystalline diamond has the potential to improve the osseointegration of orthopaedic implants compared to conventional osteo-implant materials such as titanium. However, despite the excellent biocompatibility and superior mechanical properties, the major challenge of using diamond for implants such as those used for hip arthroplasty is the limitations of microwave plasma chemical vapor deposition (CVD) techniques to synthesize diamond on complex-shaped objects. Here, for the first time we demonstrate diamond growth on titanium acetabular shells using surface wave plasma CVD method. Polycrystalline diamond coatings were synthesized at low temperatures (~400 °C) on three types of acetabular shells with different surface structure and porosity. We achieved diamond growth on highly porous surfaces designed to mimic the structure of the trabecular bone and improve osseointegration. Biocompatibility was investigated on nanocrystalline diamond (NCD) and ultrananocrystalline diamond (UNCD) coatings terminated either with hydrogen or oxygen. To understand the role of diamond surface topology and chemistry in attachment and proliferation of mammalian cells we investigated adsorption of extracellular matrix (ECM) proteins, and monitored metabolic activity of fibroblasts, osteoblasts, and bone marrow-derived mesenchymal stem cells (MSCs). The interaction of bovine serum albumin (BSA) and Type I collagen with diamond surface was investigated by confocal fluorescence lifetime imaging microscopy (FLIM). We found that proliferation of MSCs was better on hydrogen terminated UNCD than on oxygen terminated counterpart. These findings corelate to the behaviour of collagen on diamond substrates observed by FLIM. Hydrogen terminated UNCD provides better adhesion and proliferation for MSCs, compared to titanium, while growth of fibroblasts is poorest on hydrogen terminated NCD and osteoblasts behave similarly on all tested surfaces. These results open new opportunities for application of diamond coatings on orthopaedic implants.


Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 406
Author(s):  
May Tran Thi ◽  
Seokhun Kwon ◽  
Hyunil Kang ◽  
Jung-Hyun Kim ◽  
Yong-Kyu Yoon ◽  
...  

This research is conducted in order to investigate the structural and electrical characteristics of carbon nanowalls (CNWs) according to the sputtering time of interlayers. The thin films were deposited through RF magnetron sputtering with a 4-inch target (Ni and Ti) on the glass substrates, and the growth times of the deposition were 5, 10, and 30 min. Then, a microwave plasma-enhanced chemical vapor deposition (PECVD) system was used to grow CNWs on the interlayer-coated glass substrates by using a mixture of H2 and CH4 gases. The FE-SEM analysis of the cross-sectional and planar images confirmed that the thickness of interlayers linearly increased according to the deposition time. Furthermore, CNWs grown on the Ni interlayer were taller and denser than those grown on the Ti interlayer. Hall measurement applied to measure sheet resistance and conductivity confirmed that the electrical efficiency improved significantly as the Ni or Ti interlayers were used. Additionally, UV-Vis spectroscopy was also used to analyze the variations in light transmittance; CNWs synthesized on Ni-coated glass have lower average transmittance than those synthesized on Ti-coated glass. Based on this experiment, it was found that the direct growth of CNW was possible on the metal layer and the CNWs synthesized on Ni interlayers showed outstanding structural and electrical characterizations than the remaining interlayer type.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Qiang Tang ◽  
Zhibin Hu ◽  
Zechao Tao ◽  
Dan Ye ◽  
Jau Tang

AbstractTo study the combustion process of fuel in the microwave plasma torch, we designed a butane microwave plasma device exploiting a tungsten rod as an electrode. Through analysis of the image record by high-speed camera, we found that the discharge of butane microwave plasma torch is a cyclic process at atmospheric pressure at a frequency  of around 100 Hz. During the discharge, the active particles continuously diffuse from the electrode to the outside like the bloom of the flower. Then, the variation of plasma torch of jet height and temperature with microwave power is obtained. In addition, we studied the effects of different butane flow rates on the plasma torch. The results illustrate that excessive butane will lead to carbon deposition on the electrode. All in all, this work provides a new understanding of the combustion of the microwave plasma torch, which is conducive to the further development of microwave plasma in the fields of waste gas treatment, fuel combustion, and plasma engine.


Author(s):  
Steffen Pauly ◽  
Andreas Schulz ◽  
Matthias Walker ◽  
Moritz Gorath ◽  
Klaus Baumgärtner ◽  
...  

Carbon ◽  
2022 ◽  
Author(s):  
Victor Ralchenko ◽  
Vadim Sedov ◽  
Artem Martyanov ◽  
Valery Voronov ◽  
Sergey Savin ◽  
...  

CrystEngComm ◽  
2022 ◽  
Author(s):  
Wei Cao ◽  
Zhibin Ma ◽  
Hongyang Zhao ◽  
Deng Gao ◽  
Qiuming Fu

On a semi-open holder, the homoepitaxial lateral growth of single-crystal diamond (SCD) was carried out via microwave plasma chemical vapor deposition (MPCVD). By tuning and optimizing two different structures of...


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