1. Department of Physics, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
2. Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
3. Center for Hybrid Nanostructures (CHyN) and Physics Department, University Hamburg, 20146 Hamburg, Germany
4. Department of Physics, University of Mysore, Vijnana Bhavan, P.B. No. 21, Manasagangothri, Mysuru 570006, India