1. Faculty of Materials Science and Engineering, Jimma University, Jimma P.O. Box 378, Ethiopia
2. Department of Physics, College of Natural and Computational Science, Bonga University, Bonga P.O. Box 334, Ethiopia
3. Faculty of Civil and Environmental Engineering, Jimma University, Jimma P.O. Box 378, Ethiopia
4. School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, India
5. School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560, India
6. Faculty of Agricultural and Environmental Sciences, University of Rostock, Justus-Von-Liebig-Weg 6, 18059 Rostock, Germany