1. Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, Wollongong, New South Wales 2525, Australia
2. Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China
3. Institute of Physics, Chinese Academy of Science, Haidian District, Beijing 100080, China
4. State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China