1. School of Physics and Electronics, Hunan University, Changsha, China
2. School of Integrated Circuits, Tsinghua University, Beijing, China
3. School of Physics and Electronics, Central South University, Changsha, China
4. College of Electrical and Information Engineering, Hunan University, Changsha, China
5. Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
6. College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha, China