1. Research and Development Centre for Advanced Technologies in Microelectronics National Research Tomsk state University Tomsk 634050 Russia
2. R&D Department Perfect Crystals LLC Saint Petersburg 194064 Russia
3. Laboratory of Physics of Shaped Crystals Ioffe Institute of the Russian Academy of Sciences Saint Petersburg 194021 Russia
4. Department of Physics Saint Petersburg State University Saint Petersburg 199034 Russia
5. Division of Physics of Dielectrics and Semiconductors Ioffe Institute of the Russian Academy of Sciences Saint Petersburg 194021 Russia