1. National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, Ankara 06800, Turkey and Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800, Turkey
2. National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, Ankara 06800, Turkey; Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800, Turkey; and Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, Ankara 06800 Turkey