1. Institute of Materials and Quality Engineering, Faculty of Materials, Metallurgy and Recycling, Technical University of Košice, Letná 9, 042 00 Košice, Slovakia
2. Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovakia
3. Department of Physics of Condensed Matters, Faculty of Sciences, Pavol Jozef Šafárik University in Košice, Park Angelinum 9, 041 54 Košice, Slovakia
4. Nanomaterials for Electronic and Energy Applications, Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany