[1] Peking Univ, Beijing Sci & Engn Ctr Nanocarbons, Coll Chem & Mol Engn, Ctr Nanochem,Beijing Natl Lab Mol Sci, Beijing, Peoples R China
[2] Ctr Multidimens Carbon Mat, Inst Basic Sci, Ulsan, South Korea
[3] Ulsan Natl Inst Sci & Technol, Sch Mat Sci & Engn, Ulsan, South Korea
[4] Tsinghua Univ, Dept Phys, State Key Lab Low Dimens Quantum Phys, Beijing, Peoples R China
[5] Tsinghua Univ, Tsinghua Foxconn Nanotechnol Res Ctr, Beijing, Peoples R China