1. Research and Development Center for Semiconductor Lighting TechnologyInstitute of SemiconductorsChinese Academy of Sciences Beijing 100083 China
2. Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Sciences Beijing 100049 China
3. Center for Nanochemistry (CNC)Beijing Science and Engineering Center for NanocarbonsCollege of Chemistry and Molecular EngineeringPeking University Beijing 100871 China
4. Beijing Graphene Institute (BGI) Beijing 100095 China
5. Electron Microscopy Laboratoryand International Center for Quantum MaterialsSchool of PhysicsPeking University Beijing 100871 China
6. State Key Laboratory of Superlattices and MicrostructuresInstitute of SemiconductorsChinese Academy of Sciences Beijing 100083 China
7. School of Electronics and Information EngineeringHebei University of Technology Tianjin 300401 China
8. Collaborative Innovation Center of Quantum Matter Beijing 100871 China