1. Department of Nano Convergence Engineering, Jeonbuk National University, Jeonju, Jeonbuk 54896, Republic of Korea
2. Department of Precision Engineering, Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, Japan
3. Department of Physics, Tamkang University, New Taipei City, Taiwan
4. Carbon Composite Research Centre, Department of Polymer & Nanoscience and Technology, Jeonbuk National University, Jeonju, Jeonbuk 54896, Republic of Korea