1. State Key Laboratory of Electronic Thin Film and Integrated Devices School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu 610054 P. R. China
2. Yangtze Delta Region Institute (Huzhou) University of Electronic Science and Technology of China Huzhou 313001 P. R. China
3. School of Materials Science and Engineering Zhengzhou University Zhengzhou 450000 P. R. China