1. Department
of Energy Science,
BK21 Physics Division, Graphene Center, Sungkyunkwan Advanced Institute
of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of South Korea
2. LPICM CNRS, École
polytechnique, Palaiseau 91120, France
3. Center for Nanocharacterization, Korea Research Institute of Standards and Science,
Daejeon 305-340, Republic of South Korea
4. Samsung SDI Corporate R&D Center, Gongse-dong, Giheung-gu, Yongin-si, Gyeounggi-do 446-577, Republic of South Korea