1. Department of Materials
Science and Engineering and Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
2. Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 343411, Republic of Korea
3. Gyeongbuk Science & Technology Promotion Center, Gumi Electronics & Information Technology Research Institute, Gumi 39171, Republic of Korea
4. Department of Materials
Science and Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea
5. KAIST Institute for the Nano Century, Daejeon 343411, Republic of Korea