1. Materials Science Division, Department of Physics, The University of Burdwan, Golapbag, Burdwan713104, West Bengal, India
2. Department of Botany, The University of Burdwan, Golapbag, Burdwan713104, West Bengal, India
3. Department of Instrumentation Science, Jadavpur University, Jadavpur, Kolkata700032, West Bengal, India