1. Division of Nanodevices and Related Nanomaterials Suzhou Institute of Nano‐Tech and Nano‐Bionics Chinese Academy of Sciences No. 398 Ruoshui Road, SEID, Suzhou Industrial Park Suzhou Jiangsu Province 215123 P.R. China
2. 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
3. School of Nano‐Tech and Nano‐Bionics University of Science and Technology of China No. 398 Ruoshui Road, SEID, Suzhou Industrial Park Suzhou Jiangsu Province 215123 P.R. China
4. Frontier Institute of Science and Technology State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'an 710054 P.R. China