1. Centre for Advanced 2D Materials (CA2DM) and Graphene Research Centre (GRC) National University of Singapore 6 Science Drive 2 Singapore 117546 Singapore
2. Department of Physics National University of Singapore 2 Science Drive 3 Singapore 117542 Singapore
3. Institute of Materials Research and Engineering (IMRE) Agency for Science Technology and Research (A*Star) 2 Fusionopolis Way Innovis Singapore 138634 Singapore
4. Department of Materials Science and Engineering National University of Singapore 9 Engineering Drive 1 Singapore 117575 Singapore
5. Instituto Officina dei Materiali (IOM)‐CNR Laboratorio TASC Area Science Park S.S. Km 163.5 Trieste I‐34149 Italy
6. Computational Materials Science Faculty of Science and Technology and MESA+ Institute for Nanotechnology University of Twente P.O. Box 217 7500 AE Enschede The Netherlands
7. College of Science Institute of Materials Physics and Chemistry Nanjing Forestry University Nanjing 210037 P. R. China
8. Institute of Physics and Technology Ural Federal University Mira Street 19 620002 Yekaterinburg Russia
9. Advanced Light Source (ALS) Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
10. Department of Physics National Taiwan University Taipei 10617 Taiwan
11. Department of Chemistry National University of Singapore 2 Science Drive 3 Singapore 117542 Singapore
12. NanoElectronics Group MESA+ Institute for Nanotechnology University of Twente P.O. Box 217 7500 AE Enschede The Netherlands