[1] Sungkyunkwan Univ, Sch Adv Mat Sci & Engn, Suwon 440746, South Korea
[2] Sungkyunkwan Univ, SKKU Adv Inst Nanotechnol SAINT, Suwon 440746, South Korea
[3] Korea Elect Technol Inst, Energy Display R&D Div, Songnam 463816, South Korea
[4] Chung Ang Univ, Sch Elect & Elect Engn, Seoul 156756, South Korea