1. Hunan Key Laboratory of Nanophotonics and Devices
2. School of Physics and Electronics
3. Central South University
4. Changsha 410083
5. China
6. State Key Laboratory of Superlattices and Microstructures
7. Institute of Semiconductors
8. Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering
9. University of Chinese Academy of Sciences
10. Beijing 100083
11. School of Materials and Energy
12. Guangdong University of Technology
13. Guangzhou 510006
14. Department of Applied Physics
15. Hunan University
16. Changsha 410082