Fabrication of graphene from graphite by a thermal assisted vacuum arc discharge system

2017 ◽  
Vol 104 ◽  
pp. 258-265 ◽  
Author(s):  
Guo-Wei Cheng ◽  
Kevin Chu ◽  
Jeng Shiung Chen ◽  
Jeff T.H. Tsai
2019 ◽  
Vol 1393 ◽  
pp. 012050
Author(s):  
A G Nikolaev ◽  
V P Frolova ◽  
E M Oks ◽  
K P Savkin ◽  
M V Shandrikov ◽  
...  

2007 ◽  
Vol 1057 ◽  
Author(s):  
Jeff Tsung-Hui Tsai ◽  
Jason Li ◽  
Andy Tseng

ABSTRACTA rapid thermal annealing process is demonstrated for healing the defects in carbon nanotubes using a DC vacuum arc discharge system. Multi-walled carbon nanotubes (MWCNTs) grown by chemical vapor deposition at a relatively low temperature (∼650 °C) showed structural imperfections inside the tubes which are known as "bamboo-like" defects. These defects can be thermally annealed to reconstruct the graphitic structure. A vacuum arc discharge system was used to generate high temperatures (∼1800 °C) followed by rapid cooling. The MWCNTs can be rapidly annealed in such a system by several heating and cooling cycles. The annealed samples were characterized by Raman spectroscopy and transmission electron microscopy. The defects were found to be healed when the environment contained water vapor, indicating that oxygen may play an important role in breaking the imperfect graphitic structure and removing the weakly bonded defects during the rapid heating cycles. After breaking the “bamboo” segment, the graphene shell was then reconstructed during the cooling process to produce multi-shell perfection. This method produces effective defect healing and bamboo structure removal from MWCNTs.


Author(s):  
L. Wan ◽  
R. F. Egerton

INTRODUCTION Recently, a new compound carbon nitride (CNx) has captured the attention of materials scientists, resulting from the prediction of a metastable crystal structure β-C3N4. Calculations showed that the mechanical properties of β-C3N4 are close to those of diamond. Various methods, including high pressure synthesis, ion beam deposition, chemical vapor deposition, plasma enhanced evaporation, and reactive sputtering, have been used in an attempt to make this compound. In this paper, we present the results of electron energy loss spectroscopy (EELS) analysis of composition and bonding structure of CNX films deposited by two different methods.SPECIMEN PREPARATION Specimens were prepared by arc-discharge evaporation and reactive sputtering. The apparatus for evaporation is similar to the traditional setup of vacuum arc-discharge evaporation, but working in a 0.05 torr ambient of nitrogen or ammonia. A bias was applied between the carbon source and the substrate in order to generate more ions and electrons and change their energy. During deposition, this bias causes a secondary discharge between the source and the substrate.


2021 ◽  
pp. 138731
Author(s):  
Bert Scheffel ◽  
Olaf Zywitzki ◽  
Thomas Preußner ◽  
Torsten Kopte

2021 ◽  
Vol 33 (3) ◽  
pp. 037103
Author(s):  
Jia Tian ◽  
Wenzheng Liu ◽  
Wenjun Zhang ◽  
Xitao Jiang

1994 ◽  
Vol 37 (3) ◽  
pp. 300-308
Author(s):  
I. S. Abramov ◽  
V. A. Andreev ◽  
V. T. Barchenko ◽  
A. V. Gusev ◽  
A. A. Lisenkov

1992 ◽  
Vol 62 (5) ◽  
pp. 525-530
Author(s):  
G. A. Dyuzhev ◽  
S. M. Shkol'nik

Author(s):  
Qiang Sun ◽  
Qianhong Zhou ◽  
Hantian Zhang ◽  
Wei Yang ◽  
Ye Dong ◽  
...  

Abstract The separation phenomenon of light and heavy ions was widely observed experimentally in the vacuum arc discharge with multi-component composite cathode. In this work, a two-dimensional axisymmetric multi-fluid model is used to study the separation mechanism in the multi-component composite cathode vacuum arc. The multi-component vacuum arcs are simulated as a whole which includes separate cathode spot jets, the mixing region, and common arc column. The results show that the plasma jets originated from the separate cathode spot mix together to form a common arc column after a certain distance from the cathode. Due to the rapid increase of ion temperature dozens of times in mixing region of cathode spot jet, the effect of pressure gradient becomes far greater than that of the collisions between light and heavy ions. This leads to a shift in the predominant ion motion mechanism from ion-ion collision (single cathode spot jet region) to pressure expansion (the mixing region). Finally, the light ions gain higher velocities under pressure expansion. In addition, the effect of thermal conductivity and viscosity leads to the wider high temperature regions for light ions, thus making a wider distribution of corresponding ion flux. The numerical results are qualitatively consistent with the experimental results. This paper provides an insight into ion separation mechanism in the multi-component vacuum arc.


2017 ◽  
Vol 121 (14) ◽  
pp. 143302 ◽  
Author(s):  
Y. Inada ◽  
T. Kamiya ◽  
S. Matsuoka ◽  
A. Kumada ◽  
H. Ikeda ◽  
...  

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