1. Department of Physics, Indian Institute of Technology Madras, Chennai 600 036, India
2. 2D Materials Research and Innovation Group, Indian Institute of Technology Madras, Chennai 600036, India
3. Micro Nano and Bio-Fluidics Group, Indian Institute of Technology Madras, Chennai 600036, India
4. Department of Physics, Pondicherry University, Pondicherry 605014, India
5. Department of Physics, Vivekananda College, Tiruvedakam West, Madurai 625234, India