1. Department of Semiconductors and Optoelectronic Devices, Łódź University of Technology, Wólczańska 211/215, 90-924 Łódź, Poland
2. Faculty of Electrical Engineering, Częstochowa University of Technology, al. Armii Krajowej 17, 42-201 Częstochowa, Poland
3. Institute of Electrical Engineering Systems, Łódź University of Technology, B. Stefanowskiego 18/22, 90-924 Lódź, Poland