[1] Sacred Heart Coll Autonomous, Dept Phys, Tirupattur 635601, Tamil Nadu, India
[2] Univ South Africa UNISA, Nanotechnol Labs, Coll Grad Studies, UNESCO UNISA Africa Chair Nanosci, Muckleneuk Ridge,POB 392, Pretoria, South Africa
[3] Natl Res Fdn NRF, Mat Res Grp MRG, iThemba LABS, Nanosci African Network NANOAFNET, 1 Old Faure Rd,7129 POB 722, Somerset West, Western Cape Pr, South Africa