[1] Sungkyunkwan Univ, Dept Phys, Inst Basic Sci, Ctr Nanotubes & Nanostruct Composites, Suwon 440746, South Korea
[2] Sungkyunkwan Univ, Dept Chem Engn, Ctr Nanotubes & Nanostruct Composites, Suwon 440746, South Korea
[3] Iljin Nanotech Co Ltd, Seoul 157810, South Korea