KyeoReh Lee 1, Kyoohyun Kim1, Jaehwang Jung 1, JiHan Heo 2, Sangyeon Cho 3, Sangyun Lee 1, Gyuyoung Chang 4, YoungJu Jo 1, Hyunjoo Park 1 and YongKeun Park 1,*
1Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
2Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
3Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
4Hankuk Academy of Foreign Studies, Yongin 449-854, Korea
*Author to whom correspondence should be addressed.