1. Department of Physics & Astronomy and Graphene Research Institute, Sejong University, 209 Neungdong-ro, Gwangjin-Gu, Seoul 05006, South Korea
2. Department of Physics, University of Sialkot, Punjab, Pakistan
3. Department of Nanotechnology & Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-Gu, Seoul 05006, South Korea
4. Department of Physics, Riphah International University Lahore campus, Punjab, Pakistan