1. Department of Physics, Yeungnam University, Gyeongsan 38541, Republic of Korea
2. Center of Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
3. Division of convergence Technology, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
4. Major of Semiconductor Science & Technology, Jeonbuk National University, Jeonju 54896, Republic of Korea