1. Department of Physics, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
2. Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
3. Hong Kong Branch of National Precious Metals Material Engineering Research Centre, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
4. Centre for Advanced Structural Materials, Greater Bay Joint Division, Shenyang National Laboratory for Materials Science, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
5. Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, Wuhan 430074, China
6. CityU-Shenzhen Futian Research Institute, Shenzhen 518045, China