1. Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Kowloon 999077, Hong Kong, China
2. Shenzhen Research Institute, The Hong Kong University of Science and Technology, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
3. Department of Materials Science and Engineering, Shenzhen, Southern University of Science and Technology, Shenzhen 518055, China
4. Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, The Hong Kong University of Science and Technology, Kowloon 999077, Hong Kong, China