1. NanoScience Technology Center, University of Central Florida, Orlando, Florida 32826, United States
2. Department of Materials Science and Engineering, University of Central Florida, Orlando, Florida 32816, United States
3. Department of Materials Science and Engineering, Seoul National University, Seoul 08826, South Korea
4. Department of Electrical and Computer Engineering, University of Central Florida, Orlando, Florida 32816, United States
5. Analytical Research Division, Korea Basic Science Institute, Jeonju 54907, South Korea