1. Institute of Physics of the Czech Academy of Sciences, Prague 182 21, Czech Republic
2. National Technical University of Ukraine “Kyiv Polytechnic Institute,” Kyiv 03056, Ukraine
3. V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kyiv 03028, Ukraine
4. Institute of Experimental Physics II, Leipzig University, Leipzig D-04103, Germany
5. A.F. Ioffe Physical Technical Institute, RAS, St. Petersburg 194021, Russia
6. Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg 19710, Russia