1. Department of Electronic Science University of Calcutta Kolkata 700071 India
2. Thin film and Nanoscience lab Department of Physics Jadavpur University Kolkata 700032 India
3. Department of Electronics and Telecommunication Engineering Jadavpur University Kolkata 700032 India
4. Department of Applied Science and Humanities Assam University Silchar 788011 India
5. Department of Industrial Chemistry and Swami Vivekananda Research Centre Ramakrishna Mission Vidyamandira Belur Math Howrah 711202 India