1. Materials R&D Center, Samsung Advanced Institute of Technology, Mt. 14-1, Nongseo-dong, Yongin, Gyeonggi-do 446-712, Republic of Korea
2. Department of Electrical Engineering, Soongsil University, 511 Sangdo-dong, Dongjak-gu, Seoul 156-743, Republic of Korea
3. Department of Environmental Engineering and Energy, Myongji University, 116 Myongji-ro, Cheoin-gu, Yongin, Gyeonggi-do 449-728, Republic of Korea