1. Key Laboratory for the Physics and Chemistry of Nanodevices, Center for Carbon-Based Electronics, and School of Electronics, Peking University, Beijing 100871, China
2. Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
3. College of Materials and Engineering, Hunan University, Changsha 410082, China
4. State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
5. Jihua Laboratory, Foshan 528200, Guangdong, China
6. Electrical and Computer Engineering Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States