Affiliation: | a Department of Solid State Physics, Volyn National University, 13 Voli Avenue, 43025 Lutsk, Ukraine b Electrical Engineering Department, Czestochowa University of Technology, Al. Armii Krajowej 17/19, 42-200 Czestochowa, Poland c Department of Inorganic and Physical Chemistry, Volyn National University, 13 Voli Avenue, 43025 Lutsk, Ukraine |