1. Department of Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
2. Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Dalian University of Technology, Ministry of Education, School of Physics, Dalian, 116024, China
3. School of Materials Science and Engineering, Peking University, Beijing, 100871, People’s Republic of China
4. Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States