1. State
Key Laboratory of Silicon Materials, School of Materials Science and
Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
2. Beijing
Key Laboratory of Optoelectronic Functional Materials and Micro-Nano
Devices, Department of Physics, Renmin University of China, Beijing 100872, China
3. Department
of Physics, University of York, Heslington, York YO10 5DD, United Kingdom