1. Federal University of Rio de Janeiro, Nanotechnology Engineering Program, COPPE 1 , Rio de Janeiro, RJ 21941-594, Brazil
2. Universidad Tecnologica de Pereira, Plasma, Laser and Applications Laboratory, UTP 2 , Pereira, RIS 660003, Columbia
3. Federal University of Rio de Janeiro, Electrical Engineering Program, COPPE 3 , Rio de Janeiro, RJ 21941-594, Brazil
4. Fluminense Federal University, Institute of Physics 4 , Niterói, RJ 24210-346, Brazil