1. Functional Nanomaterials Research Laboratory, Department of Physics, Doon University, Dehradun, Uttarakhand 248001, India
2. Department of Applied Physics, Delhi Technological University, Rohini, Delhi 110042, India
3. Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, No. 08-03, Singapore 138634, Singapore
4. Department of Chemistry, Doon University, Dehradun, Uttarakhand 248001, India
5. Department of Physics, Guru Nanak Dev University, Amritsar, Punjab 143005, India
6. Department of Physics, SRM University-AP, Amaravati 522502, India
7. School of Engineering & Innovation, The Open University, Milton Keynes MK7 6AA, U.K.
8. Center for Nanofibers and Nanotechnology, Mechanical Engineering Department, National University of Singapore, Singapore 117576, Singapore