[1] Sungkyunkwan Univ SKKU, Sch Adv Mat Sci & Engn, Suwon 440746, South Korea
[2] Samsung Adv Inst Technol, Yongin 446712, South Korea
[3] Natl Univ Singapore, NUSNNI NanoCore, Singapore 117580, Singapore
[4] Sungkyunkwan Univ SKKU, SKKU Adv Inst Nanotechnol SAINT, Suwon 440746, South Korea
[5] Elect & Telecommun Res Inst, Taejon 305700, South Korea