1. Department of Electrical and Computer Engineering; McGill University; 3480 University Street Montreal Quebec H3A 0E9 Canada
2. Department of Electrical Engineering and Computer Science; Center for Photonics and Multiscale Nanomaterials; University of Michigan; Ann Arbor MI 48109 USA
3. Nano Electronics Lab; Samsung Advanced Institute of Technology; Suwon-si Gyeonggi-do 443-803 South Korea