| Autor: |
Jarman, R. H., Ray, G. J., Standley, R. W., Zajac, G. W. |
| Předmět: |
|
| Zdroj: |
Applied Physics Letters; 10/27/1986, Vol. 49 Issue 17, p1065, 3p |
| Abstrakt: |
The direct determination of carbon–carbon bonding in amorphous carbon thin films has been performed by core-electron energy-loss spectroscopy and cross-polarization magic-angle spinning 13C nuclear magnetic resonance (NMR) for a series of varying band-gap amorphous carbon films (1.1–3.0 eV). The amorphous carbon films were prepared using rf plasma discharge with either capacitive or inductive coupling. The core-electron energy-loss spectroscopy is shown to be quantitative by measuring the relative number of unoccupied π* and σ* states available to the C 1s core electron. Determination of the percentage of sp2 and sp3 bonded carbon atoms follows from the measured ratio of π* and σ* states. If unity cross section for the C 1s to π* and σ* core losses is assumed, the agreement with high-resolution 13C NMR determination of the sp2 and sp3 content is very encouraging. The low band-gap material (1.1 eV) has the largest sp2 content (55–60%) which decreases with increasing band gap (3.0 eV, 12–19%). The orientation dependence of the intensities of the π* and σ* loss features is not as strong as found in highly oriented pyrolytic graphite. The observation of the orientation dependence suggests that there is a tendency for the π* orbitals to be parallel to the substrate. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
