- University of Saskatchewan
B.E. in Engineering Physics
- M.Sc. in Physics
- Radiation Specialist
Cameco Corporation, Rabbit Lake Operation
Determining the sp2/sp3 Bonding Concentrations of Carbon Films
Analysis of the electronic structures of nitrogen-doped, amorphous carbon samples and of nanodiamond films are carried out in order to determine their sp2 bonding concentration. The amorphous carbon samples under consideration are deposited onto polytetrafluoroethylene (PTFE) polymer substrates by hot wire plasma sputtering of graphite in varying nitrogen concentration atmospheres. The deposition or modification of the substrateÕs surface may lend itself to increasing hardness and wear resistance. Eventually these polymer substrates may be used for applications in the field of biomaterials, focusing on cardiovascular surgery, where a low blood/surface interaction is important.
The primary technique used in this study is x-ray absorption spectroscopy, measured at the Advanced Light Source synchrotron at the Lawrence Berkeley National Laboratory, Berkeley, USA. A method of analyzing these spectra was then developed to determine the sp2 bonding concentrations in carbon films.
Through this newly developed analysis method, the sp2 bonding concentrations in these samples increases from 74 to 93% with growing nitrogen doping. The diamond films presented here are deposited on silicon wafer substrates in a methane atmosphere by microwave plasma deposition. Various deposition conditions, such as bias voltage and methane atmosphere concentration, affect the purity of the diamond film. This analysis reveals sp2 bonding concentrations in these samples from, typically, a few percent to 25%.
- 1. Determining the sp2/sp3 bonding concentrations of carbon films using X-ray absorption spectroscopy T. Hamilton, R.G. Wilks, M.V. Yablonskikh, Q. Yang, M. Foursa, A. Hirose, V.N. Vasilets, and A. Moewes, Canad. J. Phys. 86, 1401-1407 (2008).
- 2. Soft X-ray absorption and emission characterization of nanodiamond prepared by explosive detonation T. Hamilton, E.Z. Kurmaev, S.N. Shamin, P.Y. Detkov, S.I. Chukhaeva, and A. Moewes, Diamond and Related Materials 16, 350-352 (2007).
- 3. X-ray absorption of nitrogen doped amorphous carbon films for determining sp2/sp3 bonding concentrations T. Hamilton, A. Moewes, M. Foursa, and A. Hirose (accepted for Radiation Physics and Chemistry, Radiation Physics and Chemistry 75, 1613-1616 (2006).
- 4. Plasma Enhanced Synthesis of Diamond Nanocone Films Q. Yang, T. Hamilton, C. Xiao, A. Hirose, and A. Moewes, Thin Solid Films 494, 110-115 (2005).
- 5. Testing the magnetism of polymerized fullerene D.W. Boukhvalov, P.F. Karimov, E.Z. Kurmaev, T. Hamilton, A. Moewes, L.D. Finkelstein, M.I. Katsnelson, V.A. Davydov, A.V. Rakhmanina, T.L. Makarova, Y. Kopelevich, S. Chiuzbăian, and M. Neumann, Phys. Rev. B 69, 1154251-1154254 (2004).