1. Department of Physics, Thiruvalluvar Government Arts College, Rasipuram 637401, Tamil Nadu, India
2. Department of Physics, Thiru A. Govindasamy Govt. Arts College, Tindivanam 604307, Tamil Nadu, India
3. Department of Physics, Government Arts College for Women, Salem 636008, Tamil Nadu, India
4. Department of Physics, Government Arts College (Autonomous), Salem 636007, Tamil Nadu, India
5. UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, Pretoria P.O. Box 392, Gauteng Province, South Africa
6. Nanosciences African Network (NANOAFNET), Materials Research Group (MRG), iThemba LABS-National Research Foundation (NRF), 1 Old Faure Road, 7129, Somerset West P.O. Box 722, Western Cape Province, South Africa