1. SKKU Advanced Institute
of Nanotechnology (SAINT), School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
2. Photo-electronic Hybrids Research Center, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
3. Department of Chemistry, Korea University, Seoul 136-713, Republic of Korea
4. Department of Physics, Sogang University, Seoul 121-742, Republic of Korea