1. Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
2. Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
3. Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea
4. Department of Electrical and Computer Engineering, University of Minnesota,Minneapolis, Minnesota 55455, United States
5. Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030 United States
6. Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
7. Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
8. International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
9. Department of Physics, Kyung Hee University, Seoul 02447, Republic of Korea
10. Department of Information Display, Kyung Hee University, Seoul 02447, Republic of Korea
11. KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, Republic of Korea