1. Institute of Physics, Martin-Luther-University Halle-Wittenberg, Halle 06120, Germany
2. School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200086, China
3. Engineering Physics, Coburg University of Applied Sciences and Arts, Coburg 96450, Germany
4. Center for Innovation Competence SiLi-Nano, Martin-Luther-University Halle-Wittenberg, Halle 06120, Germany
5. Interdisciplinary Center of Materials Science, Martin-Luther-University Halle-Wittenberg, Halle 06120, Germany