1. Key Laboratory of Material Physics Ministry of Education School of Physics and Microelectronics Zhengzhou University Zhengzhou 450052 China
2. State Key Laboratory on Integrated Optoelectronics College of Electronic Science and Engineering Jilin University Changchun 130012 China
3. School of Physics and Electronics and Institute of Micro/Nano Photonic Materials and Applications Henan University Kaifeng 475004 China