1. Institute of Future Lighting, Academy for Engineering and Technology, Fudan University, Shanghai 200433, China
2. College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
3. Institute for Electric Light Sources, Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Fudan University, Shanghai 200433, China
4. Department of Microelectronics, Delft University of Technology, Delft 2628 CD, the Netherlands