1. Institute of Physics, Faculty of Materials Processing and Production Technology, Częstochowa University of Technology, Al. AK 19, 42-201 Częstochowa, Poland
2. Department of Semiconductor and Optoelectronic Devices, Łódź University of Technology, Wólczańska 211/215, 90-924 Łódź, Poland
3. Faculty of Electrical Engineering, Częstochowa University of Technology, al. Armii Krajowej 17, 42-201 Częstochowa, Poland