1. NANOTAM‐Nanotechnology Research CenterBilkent University 06800 Ankara Turkey
2. Department of Electrical and Electronics EngineeringBilkent University 06800 Ankara Turkey
3. Department of PhysicsMiddle East Technical University 06800 Ankara Turkey
4. Center for Solar Energy Research and Applications (GUNAM)Middle East Technical University 06800 Ankara Turkey
5. Department of Metallurgical and Materials EngineeringMiddle East Technical University 06800 Ankara Turkey
6. Department of PhysicsBilkent University 06800 Ankara Turkey
7. UNAM Institute of Materials Science and NanotechnologyBilkent University 06800 Ankara Turkey