1. Photo-electronic Hybrids Research Center, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
2. Department of Chemistry, Korea University, 1, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-701, Republic of Korea
3. SKKU Advanced Institute of Nanotechnology (SAINT) and Center for Human Interface Nano Technology (HINT), Department of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
4. Department of Physics, Sogang University, Seoul 121-742, Republic of Korea
5. Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
6. Department of Chemistry, Chung-Ang University, Seoul 156-756, Republic of Korea
7. Green School, Korea University, 1, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-701, Republic of Korea
8. Nanomaterials Science and Engineering, Korea University of Science & Technology, Daejeon 305-350, Republic of Korea