1. Rzhanov Institute of Semiconductor Physics SB RAS, Acad. Lavrentiev Ave., 13, Novosibirsk 630090, Russia
2. Department of Physics, Novosibirsk State University, Pirogov str., 1, Novosibirsk 630090, Russia
3. Nikolaev Institute of Inorganic Chemistry SB RAS, Acad. Lavrentiev Ave., 3, Novosibirsk 630090, Russia