1. Department of Physics, University of South Florida, Tampa, Florida 33620, United States
2. Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
3. Layered Materials and Device Physics Laboratory, Department of Chemistry, Physics and Atmospheric Science, Jackson State University, Jackson, Mississippi 39217, United States
4. Department of Medical Engineering, University of South Florida, Tampa, Florida 33620, United States