Affiliation: | a Dept. of Physics, St. Michael College of Engineering & Technology, Kalaiyarkoil 630551, Tamilnadu, India b Dept. of Physics, Govt. Arts College, Melur, Madurai 625106, Tamilnadu, India c Dept. of Chemical Engineering and Green Energy Center, College of Engineering, Kyung Hee University, 1Seochun, Gihung, Yongin, Gyeonggi 446-701, South Korea |