1. National Key Laboratory of Advanced Micro and Nano Manufacture Technology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
2. Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
3. Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
4. National Institute for Materials Science, Tsukuba, Ibaraki 305-00044, Japan
5. Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou 310058, People’s Republic of China