1. Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
2. Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
3. Inter-university Microelectronics Center (IMEC), Leuven 3001, Belgium
4. Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
5. National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
6. Low-dimensional Semiconductors Lab, Metallurgical and Materials Engineering, Indian Institute of Technology-Madras, Chennai, Tamilnadu 600036, India
7. Argonne National Laboratory, Lemont, Illinois 60439, United States
8. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
9. Materials Science & Engineering, University of Washington, Seattle, Washington 98195, United States
10. Department of Mechanical Engineering and Texas Materials Institute, University of Texas, Austin, Texas 78712, United States