1. Department of Physics, School of Advanced Sciences, KLE Technological University 1 , Hubballi-580031, India
2. S. S. Tegnoor Degree College 2 , Kalaburagi-585105, India
3. Government First Grade College 3 , Shahapur-585223, Yadgir, India
4. Department of Physics and Center for Nanomaterials and MEMS, Nitte Meenakshi Institute of Technology 4 , Yelahanka, Bangalore-560064, India