1. Department Physics Education, Kotebe University of Education, Addis Ababa 31248, Ethiopia
2. Department of Physics, Addis Ababa University, Addis Ababa 1176, Ethiopia
3. Department of Applied Physics, Adama Science and Technology University, P.O. Box 1888, Adama 302120, Ethiopia
4. Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Goteborg SE412 96, Sweden
5. Department of Chemistry, Addis Ababa University, Addis Ababa 33658, Ethiopia