[1] Northwestern Polytech Univ, NPU NCP Joint Int Res Ctr Adv Nanomat & Defects En, Xian 710072, Peoples R China
[2] iThemba LABS, UNESCO UNISA Africa Chair Nanosci Nanotechnol, ZA-7129 Somerset West, South Africa
[3] Quaid i Azam Univ Campus, Natl Ctr Phys, Islamabad 44000, Pakistan
[4] Natl Ctr Phys, NPU NCP Joint Int Res Ctr Adv Nanomat & Defects En, Islamabad 44000, Pakistan
[5] Imam Mohammad Ibn Saud Islamic Univ IMSIU, Coll Sci, Dept Phys, Riyadh 13318, Saudi Arabia