1. State Key Laboratory of Silicon Materials & School of Materials Science and Engineering Zhejiang University Hangzhou 310027 P. R. China
2. School of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 P. R. China
3. Institute for Material Science Synthesis and Real Structure Christian Albrechts University Kiel Kaiserstr. 2 24143 Kiel Germany
4. Laboratory of Glasses and Ceramics Institute of Chemistry CNRS-Université de Rennes I Campus de Beaulieu 35042 Rennes cedex France