1. Department of Physics, University of South Florida, Tampa, Florida 33620, United States
2. Department of Physics, King Saud University, Riyadh 11362, Kingdom of Saudi Arabia
3. Department of Medical Engineering, University of South Florida, Tampa, Florida 33620, United States
4. Materials Science Centre, India Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
5. Nanotechnology Research and Education Center, University of South Florida, Tampa, Florida 33620, United States