1. Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
2. Department of Materials Science and Engineering, Izmir Institute of Technology, Urla 35430, İzmir, Turkey
3. Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russian Federation
4. Department of Photonics, Izmir Institute of Technology, Urla 35430, İzmir, Turkey