1. State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
2. Key Laboratory of Automobile Materials Ministry of Education, College of Materials Science & Engineering, and Electron Microscopy Center, Jilin University, Changchun 130012, China
3. State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Haidian, Beijing 00084, China