[1] Kongunadu Arts & Sci Coll, Postgrad & Res Dept Phys, Nanotechnol Lab, Coimbatore 641029, Tamilnadu, India
[2] Sri Ramakrishna Mission Vidyalaya Coll Arts & Sci, Dept Phys, Nanotechnol Lab, Coimbatore 641020, Tamilnadu, India
[3] Natl Chung Hsing Univ, Dept Phys, Taichung 40227, Taiwan
[4] Sri Ramakrishna Engn Coll, Dept Nanosci & Technol, Coimbatore 641022, Tamilnadu, India
[5] Veltech Rangarajan Dr Sagunthala R&D Inst Sci & Te, Dept Phys, Chennai 600062, Tamilnadu, India
[6] Chaoyang Univ Technol, Dept Environm Engn & Management, Taichung 413310, Taiwan