1. Semiconductor Physics, Technische Universität Chemnitz, D-09107 Chemnitz, Germany
2. V. E. Lashkaryov Institute of Semiconductor
Physics, Nat. Acad. Sci. of Ukraine, Nauky Av. 45, 03028 Kyiv, Ukraine
3. Institute of Theoretical Physics, TU Bergakademie Freiberg, Leipziger Str.
23, D-09596 Freiberg, Germany
4. A. V. Rzhanov Institute of Semiconductor Physics, Pr. Lavrentieva, 13, Novosibirsk 630090, Russia
5. Novosibirsk State University, Pirogov
Str. 2, 630090, Novosibirsk, Russia
6. L. V. Pysarzhevsky Institute
of Physical Chemistry, Nat. Acad. Sci. of Ukraine, Nauky Av. 31, 03028 Kyiv, Ukraine