1. Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India
2. Department of Allied Sciences, Graphic Era University, Dehra Dun, Uttarakhand 248002, India
3. Nanoscience Laboratory, Institute Instrumentation Center, Indian Institute of Technology Roorkee, Roorkee 247667, India
4. UGC-DAE Consortium for Scientific Research, Mumbai Centre R5 Shed, BARC, Mumbai 400085, India
5. Institute of Solid State Physics, Vienna University of Technology, Weidner Hauptstrasse, 810, 1040, Vienna, Austria
6. Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Krakow, Poland