[1] Hanyang Univ, Dept Nanotechnol, Seoul 133791, South Korea
[2] Hanyang Univ, Div Adv Mat Sci & Engn, Seoul 133791, South Korea
[3] Korea Adv Inst Sci & Technol, Dept Mat Sci & Engn, Taejon 305701, South Korea
[4] Sungkyunkwan Univ, Dept Phys, Ctr Nanotubes & Nanostruct Composites, Suwon 440746, South Korea