1. Department of Materials
Science and Engineering and Inter-University Semiconductor Research
Center, Seoul National University, Seoul 151-744, Korea
2. Air Liquide Laboratories Korea, Suite 176, Yonsei Engineering Research Park, 50
Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea
3. Pohang Accelerator Laboratory, Pohang 37673, Korea
4. Dr. S.S.Bhatnagar University Institute of Chemical Engineering and
Technology, Panjab University, Chandigarh 160 014, India
5. Department of Physics, Chonbuk National University, Jeonju 54896, Korea
6. Department of
Physics and Division of Energy Systems Research, Ajou University, Suwon 16499, Korea