1. Department of Physics, Bannari Amman Institute of Technology , Sathyamangalam, Erode , Tamil Nadu, 638 401 , India
2. Department of Chemistry, Bannari Amman Institute of Technology , Sathyamangalam, Erode , Tamil Nadu, 638 401 , India
3. Department of Physics, Ramakrishna Mission Vidyalaya College of Arts and Science , Coimbatore , Tamil Nadu, 641 020 , India