[1] TS Srinivasan Ctr Polytech Coll & Adv Training CP, Dept Basic Engn, Madras 600095, Tamil Nadu, India
[2] SRM Univ, Dept Phys, Ctr Mat Sci & Nano Devices, Kancheepuram 603203, Tamil Nadu, India
[3] Loyola Coll, Dept Phys, Madras 600034, Tamil Nadu, India