1. Taras Shevchenko Kyiv National University, Faculty of Radiophysics, Electronics and Computer Systems, pr. Akademika Hlushkova 4g, 03022 Kyiv, Ukraine
2. V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, pr. Nauky 41, 03028 Kyiv, Ukraine
3. Taras Shevchenko National University of Kyiv, Faculty of Physics, pr. Akademika Hlushkova 4a, 03022 Kyiv, Ukraine
4. Institute of Physics, National Academy of Sciences of Ukraine, pr. Nauky 46, 03028 Kyiv, Ukraine