1. Department of Materials Science and Engineering Research Institute of Advanced Materials Seoul National University Seoul 08826 Republic of Korea
2. Center for Integrated Nanotechnologies Los Alamos National Laboratory Los Alamos NM 87544 USA
3. Materials Deformation Department Korea Institute of Materials Science Changwon 51508 Republic of Korea
4. Graphene Research Center and Graphene Square Inc. Advanced Institute of Convergence Technology Seoul National University Suwon 16229 Republic of Korea
5. Research Center for Materials Analysis Korea Basic Science Institute Gwahak‐ro, Yuseong‐gu Daejeon 34133 Republic of Korea
6. Division of Electronics Information and Communication Engineering Kangwon National University Samcheok 25913 Republic of Korea
7. Department of Materials Science and Engineering Korea University Seoul 02841 Republic of Korea
8. Department of Chemistry Seoul National University Seoul 08826 Republic of Korea