[1] Sri Ramakrishna Mission Vidyalaya Coll Arts & Sci, Dept Phys, Coimbatore 641020, Tamil Nadu, India
[2] Vinayaka Missions Univ, VMKV Engn Coll, Dept Phys, Nanotechnol Lab, Salem 636308, Tamil Nadu, India
[3] Chandragupt Inst Management, Ctr Appropriate Management, Patna 800001, Bihar, India