1. Temasek Laboratories, Nanyang Technological University, 50 Nanyang Drive, Singapore 637553, Singapore
2. School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
3. Key Laboratory of Laser Technology and Optoelectronic Functional Materials of Hainan Province, and School of Physics and Electronic Engineering, Hainan Normal University, No. 99 Longkun Road, Haikou 571158, China
4. State Key Lab for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, No.A35 QingHua East Road, Beijing 100083, China, and College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, No.380 Huaibei, Beijing 101408, China
5. State Key Lab of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No.3888 Dong Nanhu Road, Changchun 130033, China