1. National Laboratory of Solid State Microstructures; College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures; Nanjing University; Nanjing 210093 China
2. Division of Advanced Nanomaterials; Key Laboratory of Nanodevices and Applications; Joint Key Laboratory of Functional Nanomaterials and Devices; CAS Center for Excellence in Nanoscience; Suzhou Institute of Nano-Tech and Nano-Bionics; Chinese Academy of Sciences; Suzhou 215123 China
3. Division of Nanomaterials; Suzhou Institute of Nano-Tech and Nano-Bionics; Nanchang; Chinese Academy of Sciences; Nanchang 330200 China
4. School of Electrical and Electronic Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
5. Nano Science and Technology Institute; University of Science and Technology of China; Suzhou 215123 China
6. Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology; School of Physics Science and Engineering; Tongji University; Shanghai 200092 China