1. NanoScience Technology Center Department of Electrical and Computer Engineering University of Central Florida Orlando FL 32826 USA
2. NanoScience Technology Center University of Central Florida Orlando FL 32826 USA
3. Analytical Research Division Korea Basic Science Institute Jeonju 54907 South Korea
4. NanoScience Technology Center Department of Electrical and Computer Engineering Department of Materials Science and Engineering University of Central Florida Orlando FL 32826 USA