1. Research and Development Center for Wide Bandgap Semiconductors, Institute of Semiconductors, Chinese Academy of Sciences 1 , Beijing 100083, People’s Republic of China
2. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences 2 , Beijing 100049, People’s Republic of China
3. Jihua Lab 3 , Foshan 528200, People’s Republic of China
4. School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences 4 , Beijing 101408, People’s Republic of China