1. College of Integrated Circuits, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou 310027, China
2. College of Information Science & Electronic Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
3. Research Center for Functional Materials and Nanotechnology Innovation Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan