1. Thin Film Materials Research Group, Korea Research Institute of Chemical Technology; 141 Gajeong-ro Yuseong-Gu, Daejeon 34114 Republic of Korea
2. School of Electrical and Electronic Engineering, Yonsei University; 50 Yonsei-ro Seodaemun-Gu, Seoul 03722 Republic of Korea
3. School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology; 123 cheomdankwagi-ro Buk-Gu, Gwangju 61005 Republic of Korea