1. Department of Electrical and Computer Engineering and Advanced Materials Research Laboratory, Clemson University, Clemson, South Carolina 29634, USA
2. Department of Electrical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA
3. Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, USA
4. School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA