1. Department of Physics, College of Natural Science, Salale University, Fitche, Ethiopia
2. Department of Physics, College of Natural and Computational Science, Dambi Dollo University, Dambi Dollo, Ethiopia
3. Department of Physics, College of Natural and Computational Science, Haramaya University, Ethiopia
4. Department of Chemistry, College of Natural and Computational Science, Dambi Dollo University, Ethiopia
5. Department of Physics, Walter Sisulu University, Private Bag X-1, Mthatha, South Africa