[1] Yeungnam Univ, Dept Phys, Gyongsan 38541, South Korea
[2] Vellore Inst Technol, Ctr Nanotechnol Res, Vellore 632014, Tamil Nadu, India
[3] Yeungnam Univ, Sch Mech Engn, Gyongsan 38541, South Korea
[4] Kumoh Natl Inst Technol, Dept Appl Chem, Gumi 39177, Gyeongbuk, South Korea