1. Lobachevsky State University of Nizhny Novgorod, Gagarin av. 23/3, 603950 Nizhny Novgorod, Russia
2. Center for Semiconductor Components and Nanotechnologies, State University of Campinas, Campinas, 13083-870 SP, Brazil
3. Department of Physics and I3N, University of Aveiro, 3810-193 Aveiro, Portugal
4. National University of Science and Technology “MISiS,” 119049 Moscow, Russia