Characterization and electrochemical properties of CF4 plasma-treated boron-doped diamond surfaces

Takeshi Kondo, Hiroyuki Ito, Kazuhide Kusakabe, Kazuhiro Ohkawa, Kensuke Honda, Yasuaki Einaga, Akira Fujishima, Takeshi Kawai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

The effect of CF4 plasma etching on diamond surfaces, with respect to treatment time, was investigated using scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. SEM observations and Raman spectra indicated an increase in surface roughening on a scale of 10-20 nm, and an increase in crystal defect density was apparent with treatment time in the range of 10 s to 30 min. In contrast, alteration of the diamond surface terminations from oxygen to fluorine was found to be rather rapid, with saturation of the F/C atomic ratio estimated from XPS analysis after treatment durations of 1 min and more. The redox kinetics of Fe(CN)63-/4- was also found to be significantly modified after 10 s of CF4 plasma treatment. This behavior shows that C-F terminations predominantly affect the redox kinetics compared to the effect on the surface roughness and crystal defects. The double-layer capacitance (Cdl) of the electrolyte/CF4 plasma-treated boron-doped diamond interface was found to show a minimum value at 1 min of treatment. These results indicate that a short-duration CF4 plasma treatment is effective for the fabrication of fluorine-terminated diamond surfaces without undesirable surface damage.

Original languageEnglish (US)
Pages (from-to)48-54
Number of pages7
JournalDiamond and Related Materials
Volume17
Issue number1
DOIs
StatePublished - Jan 2008
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the CLUSTER of Ministry of Education, Culture, Sports, Science and Technology, Japan, and the Saneyoshi Scholarship Foundation (No. 1725). We are also grateful to Mr. Soukichi Funazaki in the Ohkawa group for operating the plasma etcher.

Keywords

  • Diamond film
  • Electrochemical
  • Surface characterization

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Chemistry
  • Mechanical Engineering
  • Materials Chemistry
  • Electrical and Electronic Engineering

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