1. Mackgraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil
2. Departamento de Física, UFMG, 30123-970 Belo Horizonte, Brazil
3. Centre for Advanced 2D Materials and Graphene Research Centre Faculty of Science, National University of Singapore, 119077 Singapore
4. Universidad de Antioquia, Medellin Colombia
5. Department of Physics Faculty of Science, National University of Singapore, 119077 Singapore
6. National Graduate School for Integrative Sciences & Engineering, National University of Singapore, 119077 Singapore