1. Institute of Physics, Jan Dlugosz University in Częstochowa, 13/15, al. Armii Krajowej, 42-200 Częstochowa, Poland
2. O.G. Vlokh Institute of Physical Optics, Ivan Franko National University of Lviv, 23, Dragomanov Str., 79005 Lviv, Ukraine
3. Department of Sensor and Semiconductor Electronics, Ivan Franko National University of Lviv, 107, Tarnavskoho Str., 79017 Lviv, Ukraine
4. Institute of Physics, University of Rzeszow, 1, Pigonia Str., 35-959 Rzeszow, Poland
5. Institute of Geotechnics of Slovak Academy of Sciences, 45, Watsonova Str., 04001 Košice, Slovakia
6. Department of Inorganic Chemistry, Ivan Franko National University of Lviv, 6, Kyryla i Mefodiya Str., 79000 Lviv, Ukraine
7. Faculty of Physics, Opole University of Technology, 75, Ozimska Str., 45-370 Opole, Poland
8. Department of Physics, Engineering and Astronomy, Austin Peay State University, Clarksville, TN 37044, USA