1. Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, North Carolina 27411, United States
2. Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, North Carolina 27401, United States
3. Penn State Applied Research Laboratory, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
4. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
5. Analytical Instrumentation Facility, North Carolina State University, Raleigh, North Carolina 27695, United States