1. Research and Development, Department of Physics, Erode Sengunthar Engineering College, Erode 637058, Tamil Nadu, India
2. Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials Technology Centre (NFMTC), Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
3. Photovoltaic Metrology Section, Division of Advanced Materials Devices and Metrology, CSIR-National Physical Laboratory, New Delhi 110012, India