1. School of Electrical Engineering & Computer Science, Seoul National University, Seoul, 151-742, Republic of Korea
2. Department of Chemistry Education, Seoul National University, Seoul, 151-742, Republic of Korea.
3. Department of Nano Science & Technology, Graduate School of Convergence Science & Technology, Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Seoul, 151-742, Republic of Korea
4. Nano Systems Institute & Interdisciplinary Program in Nano-Science & Technology, Seoul National University, Seoul, 151-742, Republic of Korea
5. School of Chemical & Biological Engineering, Seoul National University, Seoul, 151-742, Republic of Korea.