1. Department of Physics, Institute of Photonics and Information Technology, Jeonbuk National University, Jeonju 54896, South Korea
2. Functional Composite Materials Research Center, Korea Institute of Science and Technology, Jeonbuk 55324, South Korea
3. SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea
4. Division of Nano and Information Technology, KIST School University of Science and Technology (UST), Jeonbuk 55324, South Korea