1. Department of Physics, University of Texas at Austin, Austin, Texas 78712, United States
2. Microelectronics
Research Center, University of Texas at Austin, Austin, Texas 78758, United States
3. Department of Mechanical Engineering and the Materials
Science and Engineering Program, University of Texas at Austin, Austin, Texas 78712, United States
4. Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 689-798, Republic of Korea
5. Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea