Evolution of sp{sup 2} networks with substrate temperature in amorphous carbon films: Experiment and theory
- Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, PF-510119, 01314 Dresden (Germany)
- Technische Universitaet Dresden, 01062 Dresden (Germany)
- Instituto de Ciencia y Tecnologia de Polimeros, Consejo Superior de Investigaciones Cientificas, 28006 Madrid (Spain)
- College of Materials Science and Engineering, Southwest Jiaotong University, 610031 Chengdu (China)
The evolution of sp{sup 2} hybrids in amorphous carbon (a-C) films deposited at different substrate temperatures was studied experimentally and theoretically. The bonding structure of a-C films prepared by filtered cathodic vacuum arc was assessed by the combination of visible Raman spectroscopy, x-ray absorption, and spectroscopic ellipsometry, while a-C structures were generated by molecular-dynamics deposition simulations with the Brenner interatomic potential to determine theoretical sp{sup 2} site distributions. The experimental results show a transition from tetrahedral a-C (ta-C) to sp{sup 2}-rich structures at {approx}500 K. The sp{sup 2} hybrids are mainly arranged in chains or pairs whereas graphitic structures are only promoted for sp{sup 2} fractions above 80%. The theoretical analysis confirms the preferred pairing of isolated sp{sup 2} sites in ta-C, the coalescence of sp{sup 2} clusters for medium sp{sup 2} fractions, and the pronounced formation of rings for sp{sup 2} fractions >80%. However, the dominance of sixfold rings is not reproduced theoretically, probably related to the functional form of the interatomic potential used.
- OSTI ID:
- 20719101
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 72, Issue 1; Other Information: DOI: 10.1103/PhysRevB.72.014120; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
Similar Records
Influence of ion energy and substrate temperature on the optical and electronic properties of tetrahedral amorphous carbon ({ital ta}-C) films
Sputtered amorphous carbon films: Microstructure, density, optical and mechanical properties