1. Materials Interface Laboratory, Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea
2. Functional Ceramics Group, Korea Institute of Materials Science (KIMS), Changwon 641-831, South Korea
3. Bio-inspired Materials and Devices Laboratory (BMDL), Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061, USA
4. Materials Modeling and Characterization Department, Korea Institute of Materials Science (KIMS), Changwon 641-831, South Korea
5. School of Materials Science and Engineering, Pusan National University, Busan 609-735, South Korea