1. Institute of Nanotechnology; Karlsruhe Institute of Technology (KIT); Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
2. Department of Inorganic Chemistry; Faculty of Chemical and Food Technology; Slovak University of Technology; Bratislava 81237 Slovak Republic
3. Karlsruhe Nano-Micro Facility (KNMF); Karlsruhe Institute of Technology (KIT); Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
4. Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS); CNRS-Université de Strasbourg, 23; rue du Loess, BP 43 67034 Strasbourg cedex 2 France