1. Faculty of Physics and Center for Nanointegration Duisburg‐Essen University of Duisburg‐Essen Lotharstr. 1 47057 Duisburg Germany
2. Yuri Gagarin State Technical University of Saratov Politekhnicheskaya str. 77 Saratov 410054 Russia
3. Department of Physics Saratov State University Astrakhanskaya str. 83 Saratov 410012 Russia
4. Department of Electronic Engineering University of Rome Tor Vergata Via Cracovia, 50 Roma 00133 Italy
5. Laboratory of Biomedical Nanotechnology I. M. Sechenov First Moscow State Medical University Trubetskaya str. 8‐2 Moscow 119991 Russia
6. Institute of Structure of Matter (ISM‐CNR) SS 14 Km Trieste 34149 Italy
7. Breitmeier Messtechnik GmbH Englerstr. 27 76275 Ettlingen Germany
8. National University of Science & Technology (NUST) MISIS Leninskiy Prospekt 4 Moscow 119049 Russia