1. L.N. Gumilyov Eurasian National University 010008 Nur-Sultan Kazakhstan
2. Institute of Solid State Physics University of Latvia 8 Kengaraga LV-1063 Riga Latvia
3. Laboratory of Solid State Physics Institute of Nuclear Physics Almaty 050032 Kazakhstan
4. Department of the Semiconductor Electronics Lviv Polytechnic National University 12 Bandery St. Lviv 79046 Ukraine
5. Department of Physics and Methods of Teaching Physics Berdyansk State Pedagogical University 4 Schmidt Str. Berdyansk 71100 Ukraine