1. Department of Materials Science and Engineering and Inter-University Semiconductor Research Center, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, Republic of Korea
2. Graduate School of Engineering Practice, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, Republic of Korea
3. Department of Electrical Engineering, Myongji University, 116 Myongji-ro,
Cheoin-gu, Yongin-si, Gyeonggi-do 17058, Republic of Korea