1. Solid State Physics Laboratory, Heinrich-Heine-Universität Düsseldorf 1 , 40204 Düsseldorf, Germany
2. Material Systems for Nanoelectronics, Chemnitz University of Technology 2 , 09107 Chemnitz, Germany and , 13083-859 Campinas, SP, Brazil
3. “Gleb Wataghin” Institute of Physics, University of Campinas 2 , 09107 Chemnitz, Germany and , 13083-859 Campinas, SP, Brazil
4. Brazilian Nanotechnology National Laboratory, Brazilian Center for Research in Energy and Materials 3 , 13083-100 Campinas, SP, Brazil
5. Mackenzie Presbyterian Institute, Mackenzie Institute for Research in Graphene and Nanotechnologies—MackGraphe 4 , 01302-907 São Paulo, SP, Brazil