1. Department of Metallurgical and Materials Engineering, Iskenderun Technical University, 31200 Hatay, Turkey
2. Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, Illinois 61801, USA
3. Department of Physics, King Fahd University, Dhahran 34463, Saudi Arabia
4. Institute of Physics and Technology, 050000 Almaty, Kazakhstan
5. LED Systems Media, 050000 Almaty, Kazakhstan
6. Department of Physics, University of Jordan, 19628 Amman, Jordan