An EPR study at X- and W-band of defects in a-C:H films in the temperature range 5-300 K

B. J. Jones, R. C. Barklie*, G. Smith, H. El Mkami, J. D. Carey, S. R.P. Silva

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Electron paramagnetic resonance (EPR) measurements have been made at X-band (≈ 9.5 GHz) and W-band (≈ 95 GHz) of a-C:H films on (1 0 0) silicon substrates; the sample temperature was varied in the range 5-300 K. Two types of film were examined. The first type are amorphous hydrogenated carbon (a-C:H) films grown by plasma enhanced chemical vapour deposition (PECVD) with negative self bias voltages in the approximate range 100-500 V. The second type were initially highly polymeric-like a-C:H films grown on Si placed on the earthed electrode of a PECVD system but were subsequently implanted with either 6 × 1015 cm-2 B+ or 2 × 1016 cm-2 B+ ions. At both X- and W-band and throughout the temperature range 5-300 K the EPR signal of the carbon unpaired electrons consists of a single symmetric line with g = 2.0026 ± 0.0002. As the temperature is lowered, several samples develop a dependence on sample orientation of the external field required for resonance. This anisotropy is explained in terms of the demagnetising fields more usually encountered in ferromagnetic resonance.

Original languageEnglish
Pages (from-to)116-123
Number of pages8
JournalDiamond and Related Materials
Issue number2
Publication statusPublished - 1 Feb 2003


  • Amorphous carbon
  • Anisotropy
  • Defects
  • EPR


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