1. Key
Laboratory of Materials Physics of Ministry of Education, Department
of Physics and Engineering, Zhengzhou University, Daxue Road 75, Zhengzhou 450052, China
2. State
Key Laboratory on Integrated Optoelectronics, College of Electronic
Science and Engineering, Jilin University, Qianjin Street 2699, Changchun 130012, China
3. State
Key Laboratory of Luminescence and Applications, Changchun Institute
of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China