1. Key Laboratory of Luminescence and Optical Information
2. Ministry of Education
3. School of Science
4. Beijing JiaoTong University
5. Beijing 100044
6. Key Laboratory of Semiconductor Materials Science
7. Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices
8. Institute of Semiconductors
9. Chinese Academy of Sciences
10. Beijing
11. School of Materials Science and Engineering
12. Zhejiang University
13. Hangzhou 310027
14. P. R. China