1. Institute of Microelectronics Peking University Beijing 100871 China
2. National Key Laboratory of Science and Technology on Micro/Nano Fabrication Beijing 100871 China
3. State Key Laboratory of Integrated Optoelectronics College of Electronic Science and Engineering Jilin University 2699 Qianjin Street Changchun 130012 China
4. State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision Instrument Tsinghua University Beijing 100084 China
5. Center for Flexible Electronics Technology Tsinghua University Beijing 100084 China