1. Department of Electrical Engineering, Yale University, 15 Prospect Street, Becton 519, New Haven, Connecticut 06511, United States
2. Faculty of Engineering and Bar-Ilan Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
3. Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100 Israel
4. National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
5. Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States