1. Next-Generation Semiconductor Device Research Section, Electronics and Telecommunications Research Institute (ETRI), 218 Gajeong-ro, Daejeon, Yuseong-gu 34129, Republic of Korea
2. Semiconductor and Advanced Device Engineering, University of Science and Technology (UST), 217 Gajeong-ro, Daejeon, Yuseong-gu 34113, Republic of Korea