1. Department of Physics, Department of Electrical and Electronics Engineering, and UNAM−Institute of Materials Science and Nanotechnology, Bilkent University, TR-06800, Ankara, Turkey
2. Physical Chemistry, TU Dresden, Bergstrasse 66b, 01062 Dresden, Germany
3. Stepanov Institute of Physics, National Academy of Sciences of Belarus , Minsk, 220072, Belarus
4. School of Electrical and Electronic Engineering, Division of Microelectronics, School of Mathematical and Physical Sciences, Luminous Semiconductor Lighting and Display Center of Excellence, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore