1. Department of Physics, Engineering and Astronomy Austin Peay State University Clarksville TN 37044 USA
2. Institute of Physics University of Rzeszow Rzeszów PL‐35‐959 Poland
3. Department of Sensor and Semiconductor Electronics Ivan Franko National University of Lviv Lviv UA‐79017 Ukraine
4. Department of Nanoscience University of North Carolina Greensboro Greensboro NC 27401 USA
5. Faculty of Physics Opole University of Technology Opole PL‐45‐370 Poland
6. Institute of Archaeology University of Rzeszow Rzeszów PL‐35‐015 Poland