1. Quantum and Nano-photonics Research Laboratory, Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia Central University, Jamia Millia Islamia, New Delhi 110025, India
2. Nanotechnology Lab, School of Physical Sciences, Jawaharlal Nehru University (JNU), New Delhi 110067, India
3. CSIR − National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012, India
4. Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia Central University, New Delhi 110025, India