1. Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, P. R. China
2. School of Electronic and Information Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, P. R. China
3. Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, P. R. China
4. Key Laboratory of Extraordinary Bond Engineering and Advanced Materials Technology of Chongqing, School of Electronic Information Engineering, Yangtze Normal University, Chongqing 408100, P. R. China
5. College of Materials Science and Engineering, Sichuan University, Chengdu 610065, P. R. China
6. Engineering Research Center of Alternative Energy Materials & Devices, Ministry of Education, Sichuan University, Chengdu 610065, P. R. China