1. Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan
2. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. National Laboratory of Solid State Microstructures,
School of Electronic Science and Engineering and Collaborative Innovation
Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, China
4. School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
5. Gatan, Inc., 5794 West Las Positas Boulevard, Pleasanton, California 94588, United States
6. Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
7. Institute
of Physics, Academia Sinica, Taipei 105, Taiwan
8. Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States