1. Department of Electrical and Computer Engineering National University of Singapore Singapore 117576
2. Quantum‐Nano Matter and Device Lab State Key Laboratory of Material Processing and Die & Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China
3. Institute of Physics Academia Sinica Taipei 11529 Taiwan
4. Key Laboratory of Materials Modification by Laser Ion and Electron Beams (Ministry of Education) Dalian University of Technology Dalian 116024 China
5. Centre for Advanced 2D Materials National University of Singapore 6 Science Drive 2 Singapore 117546
6. Department of Physics National University of Singapore Singapore 117542