1. Department of Physics, Alagappa University, Karaikudi, Tamil Nadu 630 003, India
2. Department of Physics, Chandigarh University, Mohali, Punjab 140 413, India
3. School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
4. Faculty of Engineering and Science, Western Norway University of Applied Sciences, Bergen 5063, Norway