1. Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
2. Center for X-Mechanics, Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, P. R. China.
3. School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
4. Department of Mechanical Engineering and Materials Science Program, The University of Vermont, Burlington, VT 05405, USA.
5. Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials, Institute of Wenzhou, Zhejiang University, Wenzhou 325006, P.R. China.