1. Fraunhofer Institute for Electronic Nano Systems, Technologie-Campus 3, D-09126 Chemnitz, Germany
2. Chemnitz University of Technology, Center for Microtechnologies, D-09107 Chemnitz, Germany
3. Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Str. 2, D-17489 Greifswald, Germany