1. LUKASIEWICZ Research Network, PORT Polish Center for Technology Development, Stablowicka 147, 54-066 Wroclaw, Poland
2. Department of Semiconductor Materials Engineering, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
3. Institute of Experimental Physics, University of Wroclaw, Pl. Maxa Borna 9, 50-204 Wroclaw, Poland