1. Adama Science and Technology University, Department of Applied Physics, P. O. Box1888, Adama, Ethiopia
2. Oda Bultum University, Department of Physics, P. O. Box 226, Chiro, Ethiopia
3. Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida Science Campus, Johannesburg, 1710, South Africa
4. Addis Ababa University, Department of Physics, P.O. Box: 1176, Addis Ababa, Ethiopia