scholarly journals Evaluation of Hydrogen Storage Properties of Nano-Carbon Fine Particles Synthesized in Gas Phase by Plasma-Assisted Hot-Filament Chemical Vapor Deposition

2011 ◽  
Vol 54 (3) ◽  
pp. 217-219 ◽  
Author(s):  
Yumi KINOSHITA ◽  
Yoshifumi KIMURA ◽  
Masayoshi IMANO ◽  
Yasuhiro MASAKI ◽  
Yasuaki HAYASHI
Keyword(s):  
Chemical Vapor Deposition ◽  
Hydrogen Storage ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Fine Particles ◽  
Chemical Vapor ◽  
Hydrogen Storage Properties ◽  
Nano Carbon ◽  
Hot Filament ◽  
Storage Properties

Synthesis and characterization of sulfur-incorporated microcrystalline diamond and nanocrystalline carbon thin films by hot filament chemical vapor deposition

2003 ◽  
Vol 18 (2) ◽  
pp. 363-381 ◽  
Author(s):  
S. Gupta ◽  
B.R. Weiner ◽  
G. Morell
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Methane Concentration ◽  
Chemical Vapor ◽  
Sulfur Addition ◽  
Carbon Thin Films ◽  
Hot Filament

The synthesis of microcrystalline and nanocrystalline carbon thin films using sulfur as an impurity addition to chemical vapor deposition (CVD) was investigated. Sulfur-incorporated microcrystalline diamond (μc-D:S) and nanocrystalline carbon (n-C:S) thin films were deposited on Mo substrates using methane (CH4), hydrogen (H2), and hydrogen sulfide (H2S) gas feedstocks by hot-filament CVD. These films were grown under systematically varied process parameters, while the methane concentration was fixed at 0.3% and 2% for μc-D:S and n-C:S, respectively, to study the corresponding variations of the films’ microstructure. Through these studies we obtained an integral understanding of the materials grown and learned how to control key material properties. The nanocrystalline nature of the material was proposed to be due to the change in the growth mechanisms in the gas phase (continuous secondary nucleation). The growth rate (G) was found to increase with increasing TS and [H2S] in gas phase, thus following the chemisorption model that describes the surface reactions. One of the propositions for the increase was that H2S increases the production rates of methane and consequent methyl radicals without much of its own consumption, which is almost negligible and increases the carbon-containing species. This is analogous to the increase of G with increasing methane concentration, but for the relatively high S/C ratio used here, there is a possibility of its incorporation in the material, however small. This particular conjecture was verified. In this context, the results are discussed in terms of the decomposition of reactant gases (CH4/H2/H2S) that yield ionized species. The inferences drawn are compared to those grown without sulfur to study the influence of sulfur addition to the CVD.

scholarly journals Various Allotropes of Diamond Nanoparticles Generated in the Gas Phase during Hot Filament Chemical Vapor Deposition

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2504
Author(s):  
Hwan-Young Kim ◽  
Da-Seul Kim ◽  
Kun-Su Kim ◽  
Nong-Moon Hwang
Keyword(s):  
Crystal Structure ◽  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Phase Identification ◽  
Carbon Allotropes ◽  
Diamond Nanoparticles ◽  
Transmission Electron ◽  
Hot Filament

Diamond nanoparticles have been synthesized using various methods. Nanodiamonds generated in the gas phase were captured on the membrane of a transmission electron microscope grid during a hot filament chemical vapor deposition (HFCVD) diamond process. In total, ~600 nanoparticles, which were captured for 10 s in six conditions of the capture temperatures of 900 °C, 600 °C and 300 °C and the gas mixtures of 1% CH4-99% H2 and 3% CH4-97% H2, were analyzed for phase identification using high-resolution transmission electron microscopy and fast Fourier transformation. Hexagonal diamond, i-carbon, n-diamond, and cubic diamond were identified. The observation of two or more carbon allotropes captured on the same membrane suggested their coexistence in the gas phase during HFCVD. The crystal structure of carbon allotropes was related to the size of the nanodiamond. The crystal structure of the nanoparticles affected the crystal structure of diamond deposited for 8 h. Confirmation of various carbon allotropes provides new insight into the nanodiamond synthesis in the gas phase and the growth mechanism of HFCVD diamond.

Diamond nucleation by carbon fibers on unscratched substrate by hot-filament chemical vapor deposition

1994 ◽  
Vol 9 (7) ◽  
pp. 1619-1621 ◽  
Author(s):  
Yoshikazu Nakamura ◽  
Kazunori Tamaki ◽  
Yoshihisa Watanabe ◽  
Shigekazu Hirayama
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Fibers ◽  
Vapor Deposition ◽  
Fine Particles ◽  
Chemical Vapor ◽  
Nucleation Site ◽  
Cvd Method ◽  
Diamond Particles ◽  
Hot Filament Cvd ◽  
Hot Filament

In order to overcome the difficulty of nucleation of diamond particles on unscratched substrates by the chemical vapor deposition (CVD) method, carbon fibers are introduced on unscratched substrates as a nucleation site of diamond particles. With assistance of carbon fibers, diamond particles can be synthesized on unscratched silicon substrate from a gas mixture of methane and hydrogen by the hot-filament CVD method. From SEM observations, nucleation of diamond particles has been confirmed on fibers at the beginning of deposition. Fine particles have formed initially on the rugged surface of fibers, and then they grow up to be diamond particles. Detailed SEM observations reveal nucleation has occurred on irregular surfaces such as boundaries on carbon fibers. We propose that nucleation of diamond particles can be controlled by arranging carbon fibers on the substrate without applying any mechanical pretreatment.

Gas Phase Syntheses of Single-Walled Carbon Nanotubes by Chemical Vapor Deposition Using Hot filament and Plasma

2004 ◽  
Vol 43 (No. 10A) ◽  
pp. L1237-L1240 ◽  
Author(s):  
Yasuaki Hayashi ◽  
Atsuhiro Shinawaki ◽  
Shigehiro Nishino ◽  
Yoshihisa Tanaka ◽  
Mutsuaki Morita
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Hot Filament ◽  
Walled Carbon Nanotubes
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