scholarly journals Graphene Membranes for Atmospheric Pressure Photoelectron Spectroscopy

2016 ◽  
Vol 7 (9) ◽  
pp. 1622-1627 ◽  
Author(s):  
Robert S. Weatherup ◽  
Baran Eren ◽  
Yibo Hao ◽  
Hendrik Bluhm ◽  
Miquel B. Salmeron
Keyword(s):  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Graphene Membranes

Nitriding of yttria-stabilized zirconia in atmospheric pressure microwave plasma

2009 ◽  
Vol 24 (6) ◽  
pp. 2021-2028 ◽  
Author(s):  
R. Milani ◽  
R.P. Cardoso ◽  
T. Belmonte ◽  
C.A. Figueroa ◽  
C.A. Perottoni ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Zirconium Nitride ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
Yttria Partially Stabilized Zirconia

High temperature plasma nitriding of yttria-partially-stabilized zirconia in atmospheric pressure microwave plasma was investigated. The morphological, mechanical, and physicochemical characteristics of the resulting nitrided layer were characterized by different methods, such as optical and scanning electron microscopy, microindentation, x-ray diffraction, narrow resonant nuclear reaction profiling, secondary neutral mass spectrometry, and x-ray photoelectron spectroscopy, aiming at investigating the applicability of this highly efficient process for nitriding of ceramics. The structure of the plasma nitrided layer was found to be complex, composed of tetragonal and cubic zirconia, as well as zirconium nitride and oxynitride. The growth rate of the nitrided layer, 4 µm/min, is much higher than that obtained by any other previous nitriding process, whereas a typical 50% increase in Vickers hardness over that of yttria-partially-stabilized zirconia was observed.

A Study on the Damage Layer Removal of Single-Crystal Silicon Wafer After Atmospheric-Pressure Plasma Etching

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Weijia Guo ◽  
Senthil Kumar Anantharajan ◽  
Xinquan Zhang ◽  
Hui Deng
Keyword(s):  
Single Crystal ◽  
Plasma Etching ◽  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Single Crystal Silicon ◽  
Atmospheric Pressure Plasma ◽  
Etching Process ◽  
Wafer Surface ◽  
Etching Time ◽  
Crystal Silicon

Abstract In this study, atmospheric-pressure (AP) plasma generated using He/O2/CF4 mixture as feed gas was used to etch the single-crystal silicon (100) wafer and the characteristics of the etched surface were investigated. The wafer morphology and surface elemental composition were analyzed using scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The XPS results reveal that the fluorine element will be deposited on the wafer surface during the etching process when oxygen was not introduced as the feed gas. By detecting the energy and intensity of emitted particles, optical emission spectroscopy (OES) is used to identify the radicals in plasma. The fluorocarbon radicals generated during CF4 plasma ionization can form carbon fluoride polymer, which is considered as one factor to suppress the etching process. The roughness was measured to be changed with the increase in the etching time. The surface appears to be rougher at first when the plasma etching occurred on the subsurface damaged (SSD) layer, and the subsurface cracks would show on the surface after a short-time etching. After the damaged layer was fully removed, etching resulted in the formation of square-opening etching pits. During extended etching, the individual etching pits grew up and coalesced with one another; this coalescence provided an improved surface roughness. This study explains the AP plasma etching mechanism, and the formation of anisotropic surface etching pits at a microscale level for promoting the micromachining process.

scholarly journals Synthesis and Properties of Plasma-Polymerized Methyl Methacrylate via the Atmospheric Pressure Plasma Polymerization Technique

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 396 ◽  
Author(s):  
Choon-Sang Park ◽  
Eun Jung ◽  
Hyo Jang ◽  
Gyu Bae ◽  
Bhum Shin ◽  
...  
Keyword(s):  
Methyl Methacrylate ◽  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Secondary Ion Mass Spectrometry ◽  
Atmospheric Pressure Plasma ◽  
Thickness Measurement ◽  
Water Contact ◽  
Pressure Plasma ◽  
Measurement Results ◽  
The Fourier Transform

Pinhole free layers are needed in order to prevent oxygen and water from damaging flexible electrical and bio-devices. Although polymerized methyl methacrylate (polymethyl methacrylate, PMMA) for the pinhole free layer has been studied extensively in the past, little work has been done on synthesizing films of this material using atmospheric pressure plasma-assisted electro-polymerization. Herein, we report the synthesis and properties of plasma-PMMA (pPMMA) synthesized using the atmospheric pressure plasma-assisted electro-polymerization technique at room temperature. According to the Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and time of flight-secondary ion mass spectrometry (ToF-SIMS) results, the characteristic peaks from the pPMMA polymer chain were shown to have been detected. The results indicate that the percentage of hydrophobic groups (C–C and C–H) is greater than that of hydrophilic groups (C–O and O–C=O). The field emission-scanning electron microscope (FE-SEM) and thickness measurement results show that the surface morphology is quite homogenous and amorphous in nature, and the newly proposed pPMMA film at a thickness of 1.5 µm has high transmittance (about 93%) characteristics. In addition, the results of water contact angle tests show that pPMMA thin films can improve the hydrophobicity.

Chemical Vapor Deposition of Niobium Carbide using a Novel Organometallic Precursor.

1989 ◽  
Vol 168 ◽  
Author(s):  
Paul D. Stupik ◽  
Linda K. Cheatham ◽  
John J. Graham ◽  
Andrew R. Barron
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Niobium Carbide ◽  
Chemical Vapor ◽  
Stoichiometric Ratio ◽  
X Ray ◽  
Organometallic Precursor ◽  
Scanning Electron

AbstractChemical vapor deposition from (MeCp)2Nb(allyl) at atmospheric pressure yields niobium carbide films at temperatures as low as 300°C. X-ray photoelectron spectroscopy (XPS) studies indicate that the bulk films contain a carbide phase and a nearly stoichiometric ratio of niobium to carbon. The morphology of the films has been examined by scanning electron microscopy (SEM).

Photoelectron spectroscopy of wet and gaseous samples through graphene membranes

Nanoscale ◽  
2014 ◽  
Vol 6 (23) ◽  
pp. 14394-14403 ◽  
Author(s):  
Jürgen Kraus ◽  
Robert Reichelt ◽  
Sebastian Günther ◽  
Luca Gregoratti ◽  
Matteo Amati ◽  
...  
Keyword(s):  
Free Path ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
Mean Free Path ◽  
Electron Spectrometer ◽  
Dense Media ◽  
Electron Mean Free Path ◽  
Sample Environment ◽  
Graphene Membranes

Due to the short electron mean free path in dense media samples in liquid or ambient pressure environment cannot be easily characterized by photoelectron spectroscopy. We overcome this limitation by employing electron transparent graphene membranes to separate the sample environment from the vacuum conditions in the electron spectrometer.

scholarly journals Generation of Porous Alumina Layers in a Polydimethylsiloxane/Hydrogen Peroxide Medium on Aluminum Substrate in Corona Discharges

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
A. Groza ◽  
A. Surmeian ◽  
C. Diplasu ◽  
C. Luculescu ◽  
C. Negrila ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Porous Alumina ◽  
Aluminum Substrate ◽  
Corona Discharges ◽  
Negative Corona ◽  
Alumina Layer ◽  
X Ray ◽  
Anodization Process

The porous alumina (Al2O3) layer obtained at the interface between polydimethylsiloxane/hydrogen peroxide medium and aluminum substrate under charged and neutral species injection produced in negative corona discharges in air at atmospheric pressure is analyzed by different methods in this paper. The scanning electron microscopy investigations showed the uniform distribution of the pores formed in the alumina layer and their columnar structures. Both energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) measurements indicate that during the anodization process of the aluminum in the polydimethylsiloxane/hydrogen peroxide medium in corona discharge the incorporation of silicon in the structure of the alumina layer is possible.

scholarly journals Direct Exposure of Dry Enzymes to Atmospheric Pressure Non-Equilibrium Plasmas: The Case of Tyrosinase

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2181
Author(s):  
Annamaria Lapenna ◽  
Fiorenza Fanelli ◽  
Francesco Fracassi ◽  
Vincenza Armenise ◽  
Valeria Angarano ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Direct Interaction ◽  
Thin Film Deposition ◽  
Ring Structure ◽  
Film Deposition ◽  
Dielectric Barrier Discharges ◽  
Direct Exposure ◽  
Barrier Discharges ◽  
Non Equilibrium

The direct interaction of atmospheric pressure non-equilibrium plasmas with tyrosinase (Tyr) was investigated under typical conditions used in surface processing. Specifically, Tyr dry deposits were exposed to dielectric barrier discharges (DBDs) fed with helium, helium/oxygen, and helium/ethylene mixtures, and effects on enzyme functionality were evaluated. First of all, results show that DBDs have a measurable impact on Tyr only when experiments were carried out using very low enzyme amounts. An appreciable decrease in Tyr activity was observed upon exposure to oxygen-containing DBD. Nevertheless, the combined use of X-ray photoelectron spectroscopy and white-light vertical scanning interferometry revealed that, in this reactive environment, Tyr deposits displayed remarkable etching resistance, reasonably conferred by plasma-induced changes in their surface chemical composition as well as by their coffee-ring structure. Ethylene-containing DBDs were used to coat tyrosinase with a hydrocarbon polymer film, in order to obtain its immobilization. In particular, it was found that Tyr activity can be fully retained by properly adjusting thin film deposition conditions. All these findings enlighten a high stability of dry enzymes in various plasma environments and open new opportunities for the use of atmospheric pressure non-equilibrium plasmas in enzyme immobilization strategies.

One-step Synthesis of Carbon Nanotubes Network with Rich Oxygenated Functional Groups via Microwave Plasma in Atmospheric Pressure

MRS Advances ◽  
2020 ◽  
Vol 5 (52-53) ◽  
pp. 2679-2684
Author(s):  
Dashuai Li ◽  
Ling Tong ◽  
Bo Gao
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Ethanol Vapor ◽  
Transmission Electron ◽  
Synthesis Of Carbon Nanotubes ◽  
Oxygenated Functional Groups

AbstractAn atmospheric pressure microwave plasma tubular furnace apparatus (MPTF) for the rapid synthesis of carbon nanotubes (CNTs) has been developed. CNTs have been synthesized by an Argon-Hydrogen microwave plasma using ethanol vapor as carbon source with the furnace temperature of 800 °C at the atmospheric pressure. The synthesized CNTs have been analyzed by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and are shown to be multi-walled and tangled and chemically connected to form a high-density network with the diameter at the range of 25-70 nm. The measurement of X-ray photoelectron spectroscopy (XPS) indicates that a large number of oxygenated functional groups grown on the surface of CNTs. These properties proved that the CNTs could be utilized as nanoscale templates for various applications.

DLC Films Synthesized on the Ti6Al4V Alloy Surface by Plasma Gun at an Atmospheric Pressure

2011 ◽  
Vol 687 ◽  
pp. 739-744 ◽  
Author(s):  
Fei Chen ◽  
Jia Qing Chen ◽  
Hai Zhou ◽  
Cheng Ming Li
Keyword(s):  
Thin Film ◽  
Friction Coefficient ◽  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Ti6al4v Alloy ◽  
Alloy Surface ◽  
Dry Sliding ◽  
Plasma Gun

At atmospheric pressure, Diamond-Like Carbon (DLC) thin films were deposited on the Ti6Al4V alloy surface by a DBD plasma gun at low temperature (<350°C), with CH4 as a precursor and Ar as dilution gas. The structure of the DLC thin film was analyzed by Laser Raman spectroscope and X-ray photoelectron spectroscopy. The surface morphology was observed through scanning electron microscopy. The adhesion between the DLC thin film and the substrate was investigated with the scribe testing. The friction and wear behavior of the DLC thin film under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results show that it is feasible to prepare a DLC thin film of 1.0μm thickness by plasma gun. The surface roughness Ra is about 13.23nm. The DLC thin film has a good adhesion of critical load 31.0N. It has been found that the DLC thin film has excellent friction and wear-resistant behaviors. The friction coefficient of the Ti6Al4V substrate is about 0.50 under dry sliding against the steel, while the DLC thin film experiences much abated friction coefficient to 0.15 under the same testing condition.

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