1. ARTIST Lab for Artificial Electronic Materials & Technologies, School of Microelectronics, Northwestern Polytechnical University 1 , Xi'an 710072, China
2. Research & Development Institute of Northwestern Polytechnical University 2 , Shenzhen 518057, China
3. Yangtze River Delta Research Institute of NPU, No. 27 Zigang Road, Science and Education New Town 3 , Taicang 215400, China
4. Department of Physics, National University of Singapore 4 , Singapore 117542, Singapore
5. Center for Advanced 2D Materials and Graphene Research Center, National University of Singapore 5 , 6 Science Drive 2, Singapore 117546, Singapore