1. Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
2. College of Electronic and Communication Engineering, University of Chinese Academy of Sciences, Beijing 101408, China
3. State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
4. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
5. Physics Department, Lancaster University, Lancaster LA1 4YB, UK
6. Southwest Institute of Technical Physics, Chengdu 610041, China