1. Department of Physics, Pusan National University, Busan 46241, South Korea
2. Nano Hybrid Technology Research Center, Creative and Fundamental Research Division, Korea Electrotechnology Research Institute (KERI), Changwon 51543, Republic of Korea
3. Department of Nanotechnology Engineering, Pukyong National University, Busan 48513, South Korea
4. Electrical Environment Research Center, Power Grid Research Division, Korea Electrotechnology Research Institu(KERI), Changwon 51543, Republic of Korea
5. Department of Electro-Functionality Material Engineering, University of Science and Technology (UST), Changwon 51543, South Korea
6. Busan Center, Korea Basic Science Institute (KBSI), Busan 46742, South Korea