1. Łukasiewicz Research Network─PORT Polish Center for Technology Development, Wrocław 54-066, Poland
2. Faculty of Physics and Astronomy, University of Wrocław, Wrocław 50-137, Poland
3. Department of Semiconductor Materials Engineering, Wrocław University of Science and Technology, Wrocław 50-370, Poland
4. Department of Nanometrology, Wroclaw University of Science and Technology, Janiszewskiego 11/17, Wroclaw 50-372, Poland
5. Institute of Physics, Polish Academy of Sciences, Lotników 32/46, Warsaw 02-668, Poland
6. Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wrocław 50-422, Poland