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.

scholarly journals Comparison of diamond nanoparticles captured on the floating and grounded membranes in the hot filament chemical vapor deposition process

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5651-5657
Author(s):  
Hwan-Young Kim ◽  
Da-Seul Kim ◽  
Nong-Moon Hwang
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Chemical Vapor Deposition Process ◽  
Carbon Allotropes ◽  
Diamond Nanoparticles ◽  
Hot Filament ◽  
Vapor Deposition Process

Various carbon allotropes were captured on the floating and grounded membrane.

scholarly journals Metal film deposition by laser breakdown chemical vapor deposition

1986 ◽  
Vol 1 (3) ◽  
pp. 420-424 ◽  
Author(s):  
T.R. Jervis ◽  
L.R. Newkirk
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Film Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Dielectric breakdown of gas mixtures can be used to deposit thin films by chemical vapor deposition with appropriate control of flow and pressure conditions to suppress gas-phase nucleation and particle formation. Using a pulsed CO2 laser operating at 10.6 μ where there is no significant resonant absorption in any of the source gases, homogeneous films from several gas-phase precursors have been sucessfully deposited by gas-phase laser pyrolysis. Nickel and molybdenum from the respective carbonyls representing decomposition chemistry and tungsten from the hexafluoride representing reduction chemistry have been demonstrated. In each case the gas precursor is buffered with argon to reduce the partial pressure of the reactants and to induce breakdown. Films have been characterized by Auger electron spectroscopy, x-ray diffraction, transmission electron microscopy, pull tests, and resistivity measurements. The highest quality films have resulted from the nickel depositions. Detailed x-ray diffraction analysis of these films yields a very small domain size consistent with the low temperature of the substrate and the formation of metastable nickel carbide. Transmission electron microscopy supports this analysis.

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.

X-ray Characterization of Thin Diamond Films Deposited by Hot-Filament Chemical Vapor Deposition

1990 ◽  
Vol 34 ◽  
pp. 543-555
Author(s):  
Richard F. Hamilton ◽  
Diwakar Garg ◽  
Keith A. Wood ◽  
David S. Hoover
Keyword(s):  
Crystal Structure ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Free Standing ◽  
X Ray ◽  
Long Wavelength ◽  
Transmission Properties ◽  
Hot Filament

AbstractSynthesizing thin diamond films by chemical vapor deposition (CVD) is the most recent and technologically important development in the thin-film field. Thin diamond films are useful in many applications because of their unique physical, chemical, optical, and electronic properties.To assess thin diamond films’ suitability for support membranes in X-ray lithography, X-ray diffraction was used to characterize the crystal structure and orientation of these films deposited on silicon wafers by hot-filament assisted CVD. X-ray transmission properties of free-standing thin diamond films prepared by selectively etching silicon substrates were characterized by X-ray fluorescence in short and long wavelength regions.This paper discusses conventional and grazing incidence diffraction techniques used to study the crystal structure of thin diamond films and compares the results with film morphology. It also describes X-ray transmission properties of these films in terms of Beer's Law, the mass absorption coefficient, and the wavelength of attenuated radiation. Finally, it reveals the long wavelength regions for optimum X-ray lithography operations using polycrystalline diamond (PCD) film.

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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