1. Research and Development Center for Semiconductor Lighting Technology, Institute of Semiconductors, Chinese Academy of Sciences 1 , Beijing 100083, China
2. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences 2 , Beijing 100049, China
3. State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences 3 , Beijing 100083, China