1. Functional Materials and Energy Devices Laboratory, Department of Physics and Nanotechnology, S.R.M. Institute of Science and Technology, Kattankulathur 603 203, India
2. Nanotechnology Research Centre, S.R.M. Institute of Science and Technology, Kattankulathur 603 203, India
3. Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, Kaiserslautern 67663, Germany
4. Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India
5. Department of Physics, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates