1. Department of Physics, University of Alberta, Edmonton, AlbertaT6G 2E1, Canada
2. Department of Chemical & Petroleum Engineering, University of Calgary, Calgary, AlbertaT2N 1N4, Canada
3. Nanotechnology Research Centre, National Research Council of Canada, Edmonton, AlbertaT6G 2M9, Canada
4. Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AlbertaT6G 1H9, Canada
5. Department of Chemistry, University of Alberta, Edmonton, AlbertaT6G 2G2, Canada