1. Laboratory for Nanotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
2. Karlsruhe Nano and Micro Facility (KNMF) and Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
3. Chair of Power Electronics, Department of Sustainable Systems Engineering (INATECH), Albert-Ludwigs-University Freiburg, Emmy-Noether-Strasse 2, 79110 Freiburg, Germany
4. Department of Materials and Earth Sciences, Technical University Darmstadt, Alarich-Weiss-Str. 2, 64287 Darmstadt, Germany