1. Hebei Key Lab of Optic-electronic Information and Materials, the College of Physics Science and Technology, Hebei University, Baoding 071002, China
2. Institute of Physics, Chinese Academy of Sciences and University of Chinese Academy of Sciences, Beijing 100190, China
3. State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
4. Centre for Quantum Physics, Key Laboratory of Advanced Optoelxsectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
5. Department of Materials Science and Engineering, and State Key Laboratory of Terahertz and Millimeter Waves, City University of Hong Kong, Hong Kong 999077, China
6. School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China