1. Sensors and Electron Devices Directorate, United States Army Research Laboratory, Adelphi, MD, USA
2. Department of Physics, Lehigh University, Bethlehem, PA 18015, USA
3. Institute for Functional Materials and Devices, Lehigh University, Bethlehem, PA 18015, USA
4. Materials Science and Engineering Center, Columbia University, New York, NY 10023, USA
5. Department of Science and Mathematics, Fashion Institute of Technology, New York, NY 10001, USA
6. Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA