1. Department of Electrical and Computer Engineering, Inter-university Semiconductor Research Center, and Soft Foundry Institute, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
2. SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Seobu-ro, Jangan-gu, Suwon-si 16419, Gyeonggi-do, Republic of Korea