[1] Periyar Univ, Dept Phys, Salem 636011, Tamil Nadu, India
[2] JKK Nataraja Coll Arts & Sci Komarapalayam, Dept Chem, Namakkal, Tamil Nadu, India
[3] SRM Inst Sci & Technol, Directorate Res, Chennai 603203, Tamil Nadu, India
[4] SRM Inst Sci & Technol, Dept Phys & Nanotechnol, Chennai 603203, Tamil Nadu, India