1. Fondazione Istituto Italiano di Tecnologia; Graphene Labs; via Morego 30 16163 Genova Italy
2. Dipartimento di Fisica; Università della Calabria; via ponte Bucci cubo 31/C 87036 Rende Cosenza Italy
3. Department of Physics; National Cheng Kung University; 1 Ta-Hsueh Road 70101 Tainan Taiwan
4. Consiglio Nazionale delle Ricerche (CNR); Istituto Officina dei Materiali (IOM); Laboratorio TASC; Area Science Park, S.S. 14, km 163.5 34149 Trieste Italy
5. Department of Chemistry; Haiyang University; 17 Haengdang-dong Seongdong-gu Seoul 04763 South Korea
6. Theoretical Physics and Applied Mathematics Department; Ural Federal University; Mira Street 19 620002 Ekaterinburg Russia