1. Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon‐based Electronics School of Electronics Peking University Beijing 100871 P. R. China
2. Institute of Microelectronics Chinese Academy of Sciences Beijing 100029 P. R. China
3. National Space Science Center Chinese Academy of Sciences Beijing 100190 P. R. China
4. University of Chinese Academy of Sciences Beijing 100049 P. R. China
5. Beijing Institute of Carbon‐based Integrated Circuits Beijing 100195 P. R. China