Affiliation: | a Department of Physics, Faculty of Science and Arts, Gazi University, Teknikokullar, 06500 Ankara, Turkey b Nanotechnology Research Center, Bilkent University, Bilkent, 06800 Ankara, Turkey c Department of Physics, Bilkent University, Bilkent, 06800 Ankara, Turkey d Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, 06800 Ankara, Turkey |