1. Department of Electrical and Electronics Engineering, Antalya Bilim University, 07190 Antalya, Turkey
2. Nanotechnology Research Center—NANOTAM, Bilkent University, 06800 Ankara, Turkey
3. Department of Physics, Faculty of Science, Gazi University, Teknikokullar, 06500 Ankara, Turkey
4. Electrical and Electronics Engineering, Bilkent University, 06800 Ankara, Turkey