1. Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria;
2. National Centre for Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan;
3. UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Pretoria, South Africa;
4. Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Somerset West, South Africa;
5. NPU-NCP Joint International Research Center on Advanced Nanomaterials and Defects Engineering, Northwestern Polytechnical University, Xi’an, China;
6. School of Materials Science & Engineering, Northwestern Polytechnical University, Xi’an, China;
7. Department of Physics, Faculty of Natural and Applied Sciences, Coal City University, Enugu, Nigeria