1. Department of Electrical & Computer Engineering, University of Alberta, 9211-116 St., Edmonton, AB T6G 1H9, Canada
2. Nanotechnology Research Centre, National Research Council Canada, 11421 Saskatchewan Drive, Edmonton, AB T6G 2M9, Canada
3. Department of Physics, Faculty of Science, University of Alberta, Edmonton, T6G 1H9, Canada
4. Department of Materials Science and Engineering, Indian Institute of Technology Delhi, New Delhi 11016, India
5. Department of Chemical and Materials Engineering, University of Alberta, Edmonton, T6G 1H9, Canada
6. Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States