1. Chair for Integrated Systems and Photonics, Department of Electrical and Information Engineering, Faculty of Engineering, Kiel University, Kaiserstr. 2, D-24143 Kiel, Germany
2. Chair for Multicomponent Materials, Department of Materials Science, Faculty of Engineering, Kiel University, Kaiserstr. 2, D-24143 Kiel, Germany
3. Kiel Nano, Surface and Interface Science KiNSIS, Kiel University, Christian-Albrechts-Platz 4, D-24118 Kiel, Germany
4. Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany