1. School of Physics and TechnologyWuhan University Wuhan 430072 China
2. Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low‐Dimensional Structural Physics and DevicesSchool of Physics and ElectronicsHunan University Changsha 410082 China
3. Henan Key Laboratory of Infrared Materials & Spectrum Measures and ApplicationsHenan Normal University Xinxiang 453007 China
4. Department of Materials Science and EngineeringCity University of Hong Kong Tat Chee Avenue Kowloon Hong Kong SAR 999077 China