Formation of nano-columnar amorphous carbon films via electron beam irradiation

Tatsuhiko Aizawa, E. Iwamura, T. Uematsu

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Electrical beam (EB) irradiation is used to chemically modify the amorphous carbon film, a-C:H, which is prepared by the DC magnetron sputtering. The starting a-C:H film has vague columnar structure with lower density intercolumns as predicted by Thornton structure model. The EB-irradiated a-C:H film has fine nano-columnar structure with the average columnar size of 10-15 nm. This size is equivalent to the measured in-plain correlation length by the Raman spectroscopy. Little change in the sp2/sp3 bonding ratio is observed in the columnar matrix before and after EB-irradiation. Increase of sp2/sp3 ratio is noted in the intercolumns of irradiated a-C:H films. No change is detected in the hydrogen content of a-C:H films before and after EB-irradiation: 35 at% hydrogen in a-C:H. Increase of the in-plain density via EB-irradiation, is attributed to the increase of local atomic density in the intercolumns, which is measured by the electron energy zero-loss spectroscopy. This local densification is accompanied with ordering or graphitization in the intercolumns of the EB-irradiated a-C:H film. The nano-columnar a-C:H film modified by EB-irradiation has non-linear elasticity where indentation displacement should be reversible up to 8% of film thickness. Owing to this ordering and densification via EB-irradiation, softening both in stiffness and hardness takes place with increasing the irradiation time.

Original languageEnglish
Pages (from-to)6159-6166
Number of pages8
JournalJournal of Materials Science
Volume43
Issue number18
DOIs
Publication statusPublished - 2008 Sep
Externally publishedYes

Fingerprint

Carbon films
Amorphous carbon
Amorphous films
Electron beams
Irradiation
Hydrogen
Densification
Graphitization
Model structures
Indentation
Magnetron sputtering
Film thickness
Raman spectroscopy
Elasticity
Hardness
Stiffness
Spectroscopy
Electrons

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Formation of nano-columnar amorphous carbon films via electron beam irradiation. / Aizawa, Tatsuhiko; Iwamura, E.; Uematsu, T.

In: Journal of Materials Science, Vol. 43, No. 18, 09.2008, p. 6159-6166.

Research output: Contribution to journalArticle

Aizawa, Tatsuhiko ; Iwamura, E. ; Uematsu, T. / Formation of nano-columnar amorphous carbon films via electron beam irradiation. In: Journal of Materials Science. 2008 ; Vol. 43, No. 18. pp. 6159-6166.
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