A.A. Golubeva - Post-graduate Student, Department «Physics», Yuri Gagarin State Technical University of Saratov. E-mail: annamoroz@mail.ru N.M. Ushakov - Dr. Sc. (Phys.-Math.),проф, Head of Laboratory of Submicron Electronics, Saratov branch of Kotel\'nikov IRE of RAS. E-mail: nmu@bk.ru

P.I. Ropot1, A.V. Agashkov2, A.M. Varanetsky3, V.I. Kazakov4, O.V. Shakin5, S.V. Akimov6

1−3 Institute of Physics of the National Academy of Sciences of Belarus (Minsk, Belarus)

4,5 St. Petersburg State University of Aerospace Instrumentation (St. Petersburg, Russia)

5 Ioffe Institute (St. Petersburg, Russia)

6 LLC "VPG Lazerone" (Fryazino, Moscow Region, Russia)

4 vasilykazakov@mail.ru, 5 oshakin@mail.ru