[1] Govt Coll Univ, Ctr Adv Studies Phys, Lahore 54000, Pakistan
[2] King Saud Univ Riyadh, Coll Sci, Phys & Astron Dept, Riyadh, Saudi Arabia
[3] Univ Barcelona, Dept Appl Phys, C-Marti 1 Franques, 1, Barcelona 08028, Spain
[4] Univ Barcelona, Inst Nanosci & Nanotechnol IN2UB, ENPHOCAMAT Grp, C-Marti 1Franques, 1, Barcelona 08028, Spain