1. City University of Hong Kong, Department of Electrical Engineering, Hong Kong, China
2. The Hong Kong University of Science and Technology, Department of Physics, Hong Kong, China
3. Harbin Institute of Technology (Shenzhen), Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System, Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic