Raman scattering and the π-orbitals in amorphous carbon films

K. Sinha, Jose Menendez, O. F. Sankey, D. A. Johnson, W. J. Varhue, J. N. Kidder, P. W. Pastel, W. Lanford

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22 Scopus citations

Abstract

We report a Raman study of amorphous carbon films grown by different techniques. We compare Raman line shapes, depolarization ratios, and excitation profiles obtained from samples grown by rf-plasma deposition or sputtering as opposed to arc-evaporated carbon films. We find that all features of the Raman spectra are closer to results from crystalline graphite for samples deposited with an electron cyclotron resonance plasma using either a hydrocarbon gas source or a graphite sputtering target. This is surprising in view of the much larger optical band gap of these samples and also in view of recent e-2e scattering results which suggest that the π orbitals are more graphitelike in arc-evaporated carbon films. We offer a possible explanation of this paradox based on a reinterpretation of the optical properties of amorphous carbon which takes into account the special characteristics of the electronic states derived from π orbitals.

Original languageEnglish (US)
Pages (from-to)562-564
Number of pages3
JournalApplied Physics Letters
Volume60
Issue number5
DOIs
StatePublished - 1992

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    Sinha, K., Menendez, J., Sankey, O. F., Johnson, D. A., Varhue, W. J., Kidder, J. N., Pastel, P. W., & Lanford, W. (1992). Raman scattering and the π-orbitals in amorphous carbon films. Applied Physics Letters, 60(5), 562-564. https://doi.org/10.1063/1.106608