1. Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083, China
2. Research and Development Center for Semiconductor Lighting, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083, China
3. University of Chinese Academy of Sciences, Beijing 100083, China
4. State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083, China