1. Institute of Materials Engineering, College of Natural Science, University of Rzeszow, 1 Pigonia St., 35-317 Rzeszow, Poland
2. Institute of Physics, College of Natural Sciences, University of Rzeszow, 1 Pigonia St., 35-317 Rzeszow, Poland
3. Department of Semiconductor and Optoelectronic Devices, Lodz University of Technology, Wolczanska St. 211/215, 90-924 Lodz, Poland
4. Department of Physics and Chemistry of Solids, Vasyl Stefanyk Precarpathian National University, T. Shevchenko St. 57, 76018 Ivano-Frankivsk, Ukraine
5. Department of Higher Mathematics and of Physics, Faculty of Information Technology, Kryvyi Rih National University, 11 Vitaliy Matusevych St., 50027 Kryvyi Rih, Ukraine