1. Lodz University of Technology, Department of Semiconductor and Optoelectronics Devices, Wolczanska 211/215, 90-924 Lodz, Poland
2. Częstochowa University of Technology, Institute of Physics, Al. Armii Krajowej 19, 42-200 Częstochowa, Poland
3. Częstochowa University of Technology, Faculty of Electrical Engineering, A1. Armii Krajowej 17, 42-200 Częstochowa, Poland