Hydrogen plasma enhanced alignment on CNT-STM tips grown by liquid catalyst-assisted microwave plasma-enhanced chemical vapor deposition

2008 ◽  
Vol 254 (23) ◽  
pp. 7750-7754 ◽  
Author(s):  
Fa-Kuei Tung ◽  
Masamichi Yoshimura ◽  
Kazuyuki Ueda ◽  
Yutaka Ohira ◽  
Takayoshi Tanji
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Stm Tips

scholarly journals Synthesis of Multiwalled Carbon Nanotubes on Stainless Steel by Atmospheric Pressure Microwave Plasma Chemical Vapor Deposition

2020 ◽  
Vol 10 (13) ◽  
pp. 4468 ◽  
Author(s):  
Dashuai Li ◽  
Ling Tong ◽  
Bo Gao
Keyword(s):  
Carbon Nanotubes ◽  
Stainless Steel ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition

In this paper, we synthesize carbon nanotubes (CNTs) by using atmospheric pressure microwave plasma chemical vapor deposition (AMPCVD). In AMPCVD, a coaxial plasma generator provides 200 W 2.45 GHz microwave plasma at atmospheric pressure to decompose the precursor. A high-temperature tube furnace provides a suitable growth temperature for the deposition of CNTs. Optical fiber spectroscopy was used to measure the compositions of the argon–ethanol–hydrogen plasma. A comparative experiment of ethanol precursor decomposition, with and without plasma, was carried out to measure the role of the microwave plasma, showing that the 200 W microwave plasma can decompose 99% of ethanol precursor at any furnace temperature. CNTs were prepared on a stainless steel substrate by using the technology to decompose ethanol with the plasma power of 200 W at the temperatures of 500, 600, 700, and 800 °C; CNT growth increases with the increase in temperature. Prepared CNTs, analyzed by SEM and HRTEM, were shown to be multiwalled and tangled with each other. The measurement of XPS and Raman spectroscopy indicates that many oxygenated functional groups have attached to the surface of the CNTs.

Synthesis of Carbon Tubes Using Microwave Plasma-assisted Chemical Vapor Deposition

2000 ◽  
Vol 15 (8) ◽  
pp. 1749-1753 ◽  
Author(s):  
Qing Zhang ◽  
S. F. Yoon ◽  
J. Ahn ◽  
Bo Gan ◽  
Rusli ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Iron Oxide Particles ◽  
Ceramic Substrates ◽  
Field Emission Current ◽  
Electron Field ◽  
Oxide Particles

Carbon tubes were successfully produced using microwave plasma-enhanced chemical vapor deposition on silicon, quartz, and ceramic substrates. The carbon tubes, about 80–100 nm in diameter and a few tens of microns in length, were formed under methane and hydrogen plasma at 720 °C with the aid of iron oxide particles. In this approach, an average tube density of about 109 cm−2 was obtained. The crooked and nonuniform diameters of some tubes suggested that they were composed of incompletely crystallized graphitic shells due to existing defects. The characteristic of the tubes grown upward on the silicon substrate accounted for a remarkably large electron field emission current of 0.1 mA/cm2 from the surface of the tube sample at a low turn-on field of 3 V/μm.

(110)-oriented diamond films synthesized by microwave chemical-vapor deposition

1990 ◽  
Vol 5 (11) ◽  
pp. 2469-2482 ◽  
Author(s):  
Koji Kobashi ◽  
Kozo Nishimura ◽  
Koichi Miyata ◽  
Kazuo Kumagai ◽  
Akimitsu Nakaue
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Diamond Films ◽  
Film Surface ◽  
Chemical Vapor ◽  
Hydrogen Gas ◽  
X Ray ◽  
Bilayer Films

Bilayer diamond films were deposited on Si substrates by microwave-plasma chemical-vapor deposition (CVD) using a methane-hydrogen gas mixture. The first layer was deposited for 3 h using a reaction gas which was composed of 2.5 vol. % methane and 97.5 vol.% hydrogen. The deposited film consisted of very weakly (110)-oriented microcrystalline diamonds as well as amorphous carbon and graphite. In order to remove non-diamond carbons from the film surface, the specimen was treated in hydrogen plasma for 1 h. Finally, a second layer was deposited on the first layer for 14 h using a methane concentration of between 0.2 and 1.6 vol.%. It was found that the x-ray intensity of the (220) diffraction of the bilayer films was much greater than that of the (111) diffraction, indicating that the diamond grains in the second layer were strongly oriented with their crystallographic (110) planes parallel to the substrate surface. X-ray diffraction spectra of bilayer films in which the second layer was deposited for 7, 14, 21, and 35 h using two different methane concentrations, 0.3 and 1.2 vol.%, showed that within periods of up to 21 h, the (220) intensity increased with the deposition time much more quickly than the (111) intensity, indicating that the degree of (110) orientation was further enhanced as the second layer thickness increased. However, the (220) intensity decreased after 21 h, presumably due to thermal randomization. Results of scanning electron microscopy, electron diffraction, and Raman spectroscopy of the bilayer films are also presented.

Diamond nucleation on unscratched silicon substrates coated with various non-diamond carbon films by microwave plasma-enhanced chemical vapor deposition

1995 ◽  
Vol 10 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Z. Feng ◽  
M.A. Brewer ◽  
K. Komvopoulos ◽  
I.G. Brown ◽  
D.B. Bogy
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Nucleation Density ◽  
Silicon Substrates ◽  
Hard Carbon ◽  
Diamond Nucleation

The efficacy of various non-diamond carbon films as precursors for diamond nucleation on unscratched silicon substrates was investigated with a conventional microwave plasma-enhanced chemical vapor deposition system. Silicon substrates were partially coated with various carbonaceous substances such as clusters consisting of a mixture of C60 and C70, evaporated films of carbon and pure C70, and hard carbon produced by a vacuum are deposition technique. For comparison, diamond nucleation on silicon substrates coated with submicrometer-sized diamond particles and uncoated smooth silicon surfaces was also examined under similar conditions. Except for evaporated carbon films, significantly higher diamond nucleation densities were obtained by subjecting the carbon-coated substrates to a low-temperature high-methane concentration hydrogen plasma treatment prior to diamond nucleation. The highest nucleation density (∼3 × 108 cm−2) was obtained with hard carbon films. Scanning electron microscopy and Raman spectroscopy demonstrated that the diamond nucleation density increased with the film thickness and etching resistance. The higher diamond nucleation density obtained with the vacuum are-deposited carbon films may be attributed to the inherent high etching resistance, presumably resulting from the high content of sp3 atomic bonds. Microscopy observations suggested that diamond nucleation in the presence of non-diamond carbon deposits resulted from carbon layers generated under the pretreatment conditions.

scholarly journals Direct Fabrication of Carbon Nanotubes STM Tips by Liquid Catalyst-Assisted Microwave Plasma-Enhanced Chemical Vapor Deposition

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Fa-Kuei Tung ◽  
Masamichi Yoshimura ◽  
Kazuyuki Ueda
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Direct Fabrication ◽  
Electrochemically Deposited ◽  
Stm Tips

Direct and facile method to make carbon nanotube (CNT) tips for scanning tunneling microscopy (STM) is presented. Cobalt (Co) particles, as catalysts, are electrochemically deposited on the apex of tungsten (W) STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD). A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip.

Analysis of hydrogen plasma in a microwave plasma chemical vapor deposition reactor

2016 ◽  
Vol 119 (11) ◽  
pp. 113301 ◽  
Author(s):  
G. Shivkumar ◽  
S. S. Tholeti ◽  
M. A. Alrefae ◽  
T. S. Fisher ◽  
A. A. Alexeenko
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Plasma Chemical ◽  
Chemical Vapor Deposition Reactor ◽  
Plasma Chemical Vapor Deposition

A two-dimensional structure graphene STM tips fabricated by microwave plasma enhanced chemical vapor deposition

Carbon ◽  
2017 ◽  
Vol 121 ◽  
pp. 337-342 ◽  
Author(s):  
Shuai Tang ◽  
Yu Zhang ◽  
Yan Tian ◽  
Shunyu Jin ◽  
Peng Zhao ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Stm Tips
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