1. Department of Physics Acharya Nagarjuna University Nagarjuna Nagar Guntur AP 522510 India
2. Institute of Physics Opole University of Technology Opole 45370 Poland
3. School of Electronics Engineering VIT-AP University Inavolu Amaravathi AP 522237 India
4. Department of Chemistry SRM Institute of Science and Technology Kattankulathur Chennai Tamil Nadu 603203 India