* Corresponding authors

^a Department of Physics, University of Rajshahi, Rajshahi 6205, Bangladesh
E-mail: sislamru@gmail.com

^b UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria, South Africa

^c Nanosciences African Network (NANOAFNET), Materials Research Dept., iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Somerset West, PO Box 722, Western Cape 7129, South Africa