1. Division of Materials Science, Korea Basic Science Institute, Daejeon 305-333, Republic of Korea
2. Graduate School of Nanoscience and Technology (WCU), Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
3. Center for Nanobio Integration & Convergence Engineering, National Nanofab Center, Daejeon 305-806, Republic of Korea
4. Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon 305-806, Republic of Korea
5. Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1 Seochon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea
6. Department of Chemistry, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Republic of Korea
7. Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
8. Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul 100-715, Republic of Korea
9. Department of Biological Engineering, College of Engineering, Inha University, Incheon 402-751, Republic of Korea