1. CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
4. State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, & Center of Materials Science and Optoelectronics Engineering, Chinese Academy of Sciences, Beijing 100083, China
5. Dalian National Laboratory for Clean Energy, Dalian 116023, China