1. Department of Electronic Engineering and Materials Science and Technology Research Center; The Chinese University of Hong Kong; Hong Kong SAR 999077 P. R. China
2. Siyuan Laboratory; Department of Physics; Jinan University; Guangzhou Guangdong 510632 China
3. State Key Laboratory of Optoelectronic Materials and Technologies and Guangdong Province Key Laboratory of Display Material and Technology; School of Physics and Engineering; Sun Yat-sen University; Guangzhou 510275 China
4. Shenzhen Institutes of Advanced Technology; Chinese Academy of Sciences; Shenzhen 518055 China