1. Collaborative
Innovation Center of Advanced Microstructures, National Laboratory
of Solid State Microstructures and Jiangsu Provincial Laboratory for
NanoTechnology, Nanjing University, Nanjing 210093, China
2. School of Physics and Technology, Wuhan University, Wuhan 430072, China
3. College of Science, Henan University of Technology, Zhengzhou 450001, China
4. College of electronic
Engineering, Nanjing Xiaozhuang University, Nanjing 210017, China