1. Department of Laser Studies , School of Physics , Madurai Kamaraj University , Madurai-625 021 , India
2. Department of Physics , Avinasilingam University , Coimbatore-641 043 , India
3. Department of Materials Science , School of Chemistry , Madurai Kamaraj University , Madurai-625 021 , India
4. Department of Materials Science and Engineering , Michigan Technological University , Houghton , MI 49931, USA
5. Department of Solar Energy , Institute for Energy Technology , Instituttveien 18 , Kjeller 2007 , Norway
6. Indian Institute of Science Education and Research Thiruvananthapuram , India