[1] Rzhanov Inst Semicond Phys SB RAS, 13 Lavrentiev aven, Novosibirsk 630090, Russia
[2] Novosibirsk State Tech Univ, 20 K Marx str, Novosibirsk 630073, Russia
[3] Novosibirsk State Univ, Dept Phys, Pirogov Str 1, Novosibirsk 630090, Russia
[4] North Eastern Fed Univ, Inst Phys & Technol, 58 Belinsky str, Yakutsk 677027, Russia