Valence-band electronic structure evolution of graphene oxide upon thermal annealing for optoelectronics

MPA-11 Materials Synthesis and Integrated Devices (MSID), Materials Physics and Applications (MPA) Division, Mail Stop: K763, Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico 87545, USA 2 Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan 3 Center for Integrated Nanotechnologies (CINT), MPA Division, Mail Stop: K771, LANL, P.O. Box 1663, Los Alamos, New Mexico 87545, USA Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546 Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, UK WPI Advanced Institute for Materials Research (AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan Quantum Beam Science Directorate, Japan Atomic Energy Agency, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan Department of Materials Science and Engineering, Akita National College of Technology, 1-1 Bunkyo-machi, Iigima, Akita 011-8511, Japan T-1 Physics and Chemistry ofMaterials, Theoretical Division,Mail Stop: B221, LANL, P.O. Box 1663, Los Alamos, NewMexico 87545, USA Center for Nonlinear Studies (CNLS), Theoretical Division,Mail Stop: B258, LANL, P.O. Box 1663, LosAlamos, NewMexico 87545, USA Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan Department of Materials Science and Engineering, Rutgers University, 607 Taylor Road Piscataway, New Jersey 08854, USA