1. Department of Electronic Engineering; School of Information Science and Engineering; Xiamen University; Xiamen 361005 China
2. National Laboratory of Solid State Microstructures; Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences; Nanjing University; Nanjing 210093 China
3. Department of Physics; East China University of Science and Technology; Shanghai 200237 China
4. Center for Display Research Department of Electronic and Computer Engineering; Hong Kong University of Science and Technology; Clear Water Bay Kowloon Hong Kong 999077 China