1. Chernivtsi Department; Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine; str. Iryny Vilde 5 58001 Chernivtsi Ukraine
2. Kurdyumov Institute of Metallophysics; National Academy of Sciences of Ukraine; blvd. Akademika Vernadskogo 03680 Kyiv Ukraine
3. Lashkaryov Institute of Semiconductor Physics; National Academy of Sciences of Ukraine; pr. Nauky 4 03028 Kyiv Ukraine