1. State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123, China
4. Microsystem & Terahertz Research Center, Chinese Academy of Engineering Physics, Chengdu 610200, China
5. State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130023, China