1. State Key Laboratory of Electronic Thin Films and Integrated Devices; University of Electronic Science and Technology of China; Chengdu 610054 P. R. China
2. School of Automation Engineering; University of Electronic Science and Technology of China; Chengdu 610054 P. R. China
3. State Key Laboratory of Material Processing and Die & Mould Technology; School of Materials Science and Engineering; Huazhong University of Science and Technology; Wuhan 430074 P. R. China
4. College of Physics, Optoelectronics and Energy; Center for Energy Conversion Materials & Physics (CECMP); Soochow University; Suzhou 215006 P. R. China