1. Department of Chemical & Petroleum Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
2. Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
3. Nanotechnology Research Centre, National Research Council of Canada, Edmonton, AB T6G 2M9, Canada
4. Department of Chemistry, University of British Columbia, Kelowna, BC V1V 1V7, Canada