1. International
and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, P.D. Hills, Kottayam, Kerala 686560, India
2. School
of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560, India
3. Centre
for Nanoscience and Nanotechnology, Department of Basic Sciences, Amal Jyothi College of Engineering, Kottayam, Kerala, India
4. School
of Chemical Sciences, Mahatma Gandhi University, Kottayam, Kerala 686560, India