1. Nanophotonic and Optoelectronic Devices Laboratory, Department of Physics, Cochin University of Science and Technology, Cochin 682022, Kerala, India
2. Centre of Excellence in Advanced Materials, Cochin University of Science and Technology, Cochin 682022, Kerala, India
3. Inter University Center for Nanomaterials and Devices (IUCND), Cochin University of Science and Technology, Cochin 682022, Kerala, India