[1] DIT Univ, Dept Phys, Dehra Dun 248009, Uttar Pradesh, India
[2] GVM Girls Coll, Dept Phys, Sonepat 131001, India
[3] Hindu Coll, Dept Phys, Sonepat 131001, India
[4] Solid State Phys Lab, Delhi 110054, India
[5] DIT Univ, Dehra Dun 248009, Uttar Pradesh, India