skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Influence of the filling gas on plasma focus assisted diamondlike carbon coating at room temperature

Abstract

Amorphous diamondlike carbon films (up to 60 {mu}m thick) are deposited by dense plasma focus system using nitrogen, methane, and neon gases. The peak intensity ratio of the D-band to G-band (I{sub D}/I{sub G}) and the G-peak position in the Raman spectra are used to characterize the films deposited on silicon substrate placed at different axial and angular positions with respect to focus axis. Stress and sp{sup 2} cluster size present in the films are discussed with shift in G-peak position, since higher sp{sup 2} content and residual compressive growth stress shifts the G-peak position to higher frequencies. The peak intensity ratio I{sub D}/I{sub G} is related to sp{sup 3}/sp{sup 2} ratio to estimate the fourfold carbon networks. Thickness values obtained by cross-sectional scanning electron microscopy point toward the high film deposition rates. X-ray diffraction spectra verify the deposition of amorphous carbon a-C films which identifies no crystalline peak.

Authors:
; ;  [1]
  1. Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)
Publication Date:
OSTI Identifier:
20982752
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 6; Other Information: DOI: 10.1063/1.2713086; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMORPHOUS STATE; CHEMICAL VAPOR DEPOSITION; COATINGS; DIAMONDS; METHANE; NEON; NITROGEN; PLASMA; PLASMA FOCUS; RAMAN SPECTRA; RESIDUAL STRESSES; SCANNING ELECTRON MICROSCOPY; SILICON; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; X-RAY DIFFRACTION

Citation Formats

Zeb, Shaista, Murtaza, Ghulam, and Zakaullah, M. Influence of the filling gas on plasma focus assisted diamondlike carbon coating at room temperature. United States: N. p., 2007. Web. doi:10.1063/1.2713086.
Zeb, Shaista, Murtaza, Ghulam, & Zakaullah, M. Influence of the filling gas on plasma focus assisted diamondlike carbon coating at room temperature. United States. doi:10.1063/1.2713086.
Zeb, Shaista, Murtaza, Ghulam, and Zakaullah, M. Thu . "Influence of the filling gas on plasma focus assisted diamondlike carbon coating at room temperature". United States. doi:10.1063/1.2713086.
@article{osti_20982752,
title = {Influence of the filling gas on plasma focus assisted diamondlike carbon coating at room temperature},
author = {Zeb, Shaista and Murtaza, Ghulam and Zakaullah, M.},
abstractNote = {Amorphous diamondlike carbon films (up to 60 {mu}m thick) are deposited by dense plasma focus system using nitrogen, methane, and neon gases. The peak intensity ratio of the D-band to G-band (I{sub D}/I{sub G}) and the G-peak position in the Raman spectra are used to characterize the films deposited on silicon substrate placed at different axial and angular positions with respect to focus axis. Stress and sp{sup 2} cluster size present in the films are discussed with shift in G-peak position, since higher sp{sup 2} content and residual compressive growth stress shifts the G-peak position to higher frequencies. The peak intensity ratio I{sub D}/I{sub G} is related to sp{sup 3}/sp{sup 2} ratio to estimate the fourfold carbon networks. Thickness values obtained by cross-sectional scanning electron microscopy point toward the high film deposition rates. X-ray diffraction spectra verify the deposition of amorphous carbon a-C films which identifies no crystalline peak.},
doi = {10.1063/1.2713086},
journal = {Journal of Applied Physics},
number = 6,
volume = 101,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • Diamondlike carbon (DLC) thin films have been prepared by chemical vapor deposition assisted by electron cyclotron resonance plasma at low pressure with radio frequency (rf) power applied to the substrate. The microstructure studies by transmission electron microscopy and electron energy loss spectroscopy show the existence of nanocrystalline diamond grains in DLC films prepared at 0.35 Pa. The cluster{close_quote}s size varies from 4 to 30 nm with bias voltage (V{sub b}) varying from {minus}200 to {minus}600V. A phase transition from hexagonal to cubic diamond was also observed with increasing V{sub b}. {copyright} {ital 1997 American Institute of Physics.}
  • We report on the synthesis of Ti-containing diamondlike hydrocarbon (Ti-DLC) coatings by plasma-assisted physical vapor deposition and the characterization of coating microstructure and mechanical properties. We find that Ti-DLC coatings with Ti compositions higher than 5.5 at.{percent} are composites consisting of nanocrystalline TiC in an amorphous hydrocarbon matrix. The hardness and elastic modulus of Ti-DLC coatings are found to increase monotonically with increasing Ti composition, while the ratio of the hardness to the modulus remains approximately constant. {copyright} {ital 1998 American Institute of Physics.}
  • Diamondlike carbon (DLC) was deposited on silicon using a plasma immersion ion deposition (PIID) method. Inductive radio-frequency plasma sources were used to generate Ar and C{sub 2}H{sub 2} plasmas at low gas pressures ranging from 0.04 to 0.93 Pa. The film stress and hardness were sharply dependent upon bias voltage at an operating pressure of 0.04 Pa. A maximum hardness of 30 GPa and compressive stress of 9 GPa was observed at a pulsed bias of {minus}150 V bias (carbon energy of 80 eV). The mechanical properties of DLC films are correlated with UV Raman peak positions which infer sp{supmore » 3}-bonded carbon contents. {copyright} {ital 1998 American Institute of Physics.}« less
  • The behavior of current drop and its correlation with ion beam emission during the radial phase of a high inductance low energy Mather type plasma focus device have been studied. The study includes two ranges of filling gas pressure, namely the low range of 0.2-0.8 mbar and the high range of 0.8-1.5 mbar. Two different current simulation processes were performed to aid the interpretation of the experimental results. Within the low range of operating pressure, an acceptable match between the computed and experimental current signals was achieved when the effects of anomalous resistances were contemplated. While in the high rangemore » of pressure, the computed and experimental current traces were in line even without considering the effects of anomalous resistances. The analysis shows that by decreasing the filling gas pressure the effects of instabilities are intensified. The computed and experimental current traces, along with ion beam signals gathered from a faraday cup, show that there is a strong correlation between the intensity of ion beam and its duration with the current drop during the radial phase.« less
  • The paper reports on experimental studies of processes of the interaction of pulsed streams of fast deuterium ions (E{sub i}{approx}100 keV) and dense deuterium plasma (v{sub pl}>10{sup 7} cm/s) with samples made of carbon and tungsten. Experiments were performed in the large PF-1000 plasma-focus facility with the charging energy of 481 kJ and with the pure deuterium filling. Power flux density of plasma/ions streams was q = 10{sup 7}-10{sup 10} W/cm{sup 2} and the pulse length was from 10{sup -7} s to 10{sup -6} s, whereas the duration of heat pulses (due to a secondary plasma at the target's surface)more » was 10{sup -4} s. The stainless steel, tungsten and carbon-tungsten samples were placed in the zone of their strong melting and evaporation or in the zone without their melting. Each sample was exposed to 1 through 10 discharges, and the irradiated samples were investigated with optical-, electron- and atomic-force-microscopes. The interaction of intense plasma-ion pulses with the carbon-tungsten samples caused the formation of a wave-like relief on sample surfaces, the evident erosion of the sample material, and the creation of numerous micro-cracks. It was also found that about 200-nm-thick layer of the irradiated tungsten sample contained many melted fragments of nm-dimensions. The results might be useful for estimations of tungsten behavior in extreme situations (e.g. disruptions) expected in fusion reactors with magnetic plasma confinement.« less