1. Key Laboratory of Materials Physics of Ministry of Education School of Physics and Microelectronics Zhengzhou University Daxue Road 75 Zhengzhou 450052 China
2. Institute of Microstructure and Property of Advanced Materials Beijing Key Lab of Microstructure and Property of Advanced Materials Faculty of Materials and Manufacturing Beijing University of Technology Beijing 100124 China
3. State Key Laboratory on Integrated Optoelectronics College of Electronic Science and Engineering Jilin University Changchun 130012 China