1. School of Physics and Electronics Henan University Kaifeng 475004 China
2. School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China (UESTC) Chengdu 610054 P. R. China
3. Key Laboratory for Special Functional Materials of Ministry of Education Collaborative Innovation Center of Nano Functional Materials and Applications, and School of Materials Science and Engineering Henan University Kaifeng 475001 China
4. Physics Research Center for Two‐Dimensional Optoelectronic Materials and Devices School of Physics and Electronics Henan University Kaifeng 475004 China