[1] Riphah Int Univ, Dept Phys, Lahore, Pakistan
[2] King Saud Univ, Coll Sci, Dept Phys & Astron, Riyadh, Saudi Arabia
[3] Univ Hamburg, Ctr Hybrid Nanostruct CHyN, Hamburg, Germany
[4] Univ Hamburg, Fachbereich Phys, Hamburg, Germany
[5] Univ Management & Technol, Dept Phys, Lahore, Pakistan