Influence of doping (Ti, V, Zr, W) and annealing on the sp{sup 2} carbon structure of amorphous carbon films
- Max-Planck-Institut fuer Plasmaphysik, Materials Research, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany)
- Forschungszentrum Karlsruhe, Institute of Materials Research I, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)
The influence of the transition metal (Ti, V, Zr, W) doping on the carbon matrix nanostructuring during the thin film growth and subsequent annealing is investigated. Pure and metal-doped amorphous carbon films (a-C, a-C:Me) were deposited at room temperature by nonreactive magnetron sputtering. The carbon structure of as-deposited and postannealed (up to 1300 K) samples was analyzed by x-ray diffraction (XRD) and Raman spectroscopy. The existence of graphenelike regions in a-C is concluded from a (10) diffraction peak. A comparison of the XRD and Raman results suggests that XRD probes only the small amount of 2-3 nm large graphenelike regions, whereas the majority of the sp{sup 2} phase is present in smaller distorted aromatic clusters which are probed only by Raman spectroscopy. Annealing leads to an increase in the graphene size and the aromatic cluster size. During the carbon film growth the addition of metals enhances ordering of sp{sup 2} carbon in sixfold aromatic clusters compared to a-C; Ti, and Zr showing the strongest effect, W the lowest. This order qualitatively corresponds with the catalytic activity of the respective carbides found during graphitization of carbide-doped graphites published in the literature. With annealing, carbide crystallite formation and growth occurs in a-C:Me films, which destroys the initial carbon structure, reduces the size of the initially formed aromatic clusters and the differences in carbon structure introduced by different dopants. For high annealing temperatures the carbon structure of a-C:Me films is similar to that of a-C, and is determined only by the annealing temperature.
- OSTI ID:
- 21186012
- Journal Information:
- Journal of Applied Physics, Vol. 105, Issue 3; Other Information: DOI: 10.1063/1.3075843; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Iron-Doped Carbon Aerogels: Novel Porous Substrates for Direct Growth of Carbon Nanotubes
Bulk diffusion induced structural modifications of carbon-transition metal nanocomposite films