1. Key Laboratory of
Optoelectronics Information Technology, Ministry of Education, School
of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
2. Tianjin Key Laboratory of Low Dimensional Materials Physics
and Preparing Technology, School of Science, Tianjin University, Tianjin 300072, China
3. Center of
Material Science, National University of Defense Technology, Changsha 410073, China