1. Dept. of Physics, Yeungnam University, Gyeongsan-si, Gyeongbuk, Korea
2. Department of Digital Display Engineering, Hoseo University, Asan-shi, Chungnam, Korea
3. School of Green Energy & Semiconductor Engineering, Hoseo University, Asan-shi, Chungnam, Korea
4. Fusion Technology Lab, Hoseo University, Asan-shi, Chungnam, Korea