1. School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Chonbuk National University, Jeonju 54899, South Korea
2. Korea Atomic Energy Research Institute, Jeonbuk 56212, South Korea
3. Nano-Photonics Convergence Technology Group, Korea Institute of Industrial Technology, Gwangju 61012, South Korea
4. Korea Institute of Ceramic Engineering and Technology, Jinju 506-101, South Korea