1. Graphene Research Center, KAIST Institute for the Nano Century, School of Mechanical; Aerospace and Systems Engineering; Division of Ocean Systems Engineering; Korea Advanced Institute of Science and Technology (KAIST); 335 Gwahak-ro Yuseong-gu, Daejeon 305-701 Republic of Korea
2. School of Chemical and Biomolecular Engineering; Korea Advanced Institute of Science and Technology (KAIST); 335 Gwahak-ro Yuseong-gu, Daejeon 305-701 Republic of Korea
3. Micro Device & Machinery Solution Division; SAMSUNG Techwin R&D Center; Seongnam-si, Gyeonggi-do 463-400 Republic of Korea
4. Department of Materials Science and Engineering and the Department of Mechanical Aerospace, and Nuclear Engineering; Rensselaer Polytechnic Institute; 110 8 Street Troy, New York 12180 USA