Decreased hydrogen content in diamond-like carbon grown by CH4/Ar photoemission-assisted plasma chemical vapor deposition with CO2 gas

Shuichi Ogawa, Rintaro Sugimoto, Nobuhisa Kamata, Yuji Takakuwa

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


In this study, we tried to decrease the hydrogen content in diamond-like carbon (DLC) grown by photoemission-assisted plasma enhanced chemical vapor deposition (PA-PECVD) using Ar/CH4 mixed with CO2. When the CO2 flux was changed from 0 to 10 sccm with the Ar and CH4 fluxes maintained at 50 and 10 sccm, respectively, the growth rate decreased from 11 to 3 μm/h. Secondary mass spectroscopy measurements confirmed that the amount of O mixed into the DLC was increased through incorporation of CO2 into feed gas flow. The O concentration in the DLC was quantitatively evaluated by X-ray photoelectron spectroscopy (XPS) to be 0.6 atomic % at a CO2 flow ratio of 14%. Raman spectroscopy and XPS revealed that the amount of H trapped in the DLC decreased as the CO2 flow ratio was increased and the sp3/sp2 ratio remained almost unchanged. These results were interpreted by a model involving O radicals acting on the DLC surface associated with CO/CO2 and H2O, resulting in a decrease of the growth rate and H content. A portion of the O radicals also became incorporated into the DLC as C–O–C bonds.

Original languageEnglish
Pages (from-to)863-867
Number of pages5
JournalSurface and Coatings Technology
Publication statusPublished - 2018 Sep 25


  • Diamond-like carbon
  • Photoemission-assisted plasma
  • Plasma enhanced CVD
  • Raman spectroscopy
  • X-ray photoelectron spectroscopy

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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