1. Key Lab of Semiconductor Materials Science Institute of Semiconductors Chinese Academy of Sciences Beijing 100 083 China
2. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100 049 China
3. School of Microelectronics University of Chinese Academy of Sciences Beijing 100 049 China
4. Institute of Semiconductors, Chinese Academy of Sciences Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices Beijing 100 083 China
5. State Key Laboratory of Crystal Materials Shandong University Jinan 250 100 China