1. nanotech@surfaces Laboratory, Empa − Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
2. Department of Physics, University of California, Berkeley, California 94720, United States
3. Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511, United States
4. Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16082, United States
5. Two-Dimensional Crystal Consortium, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
6. Department of Chemistry and Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States