1. Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, P. R. China
2. State Key Lab of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
3. Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China