1. Interdisciplinary School of
Green Energy and KIER-UNIST Advanced Center for Energy, Low Dimensional
Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South
Korea
2. Department of Physics
and EHSRC, University of Ulsan, Ulsan 680-749,
South Korea
3. Department of
Materials Physics, Dong-A University, Busan
604-714, South Korea