1. Thin Film Materials Research Group; Korea Research Institute of Chemical Technology (KRICT); Yuseong Post Office Box 107 Daejeon 305-600 Republic of Korea
2. Department of Chemistry; Chung-Ang University; 84 Heukseok-ro Dongjak-gu, Seoul 156-756 Korea
3. Department of Materials Science and Engineering; Hongik University; Seoul 121-791 Republic of Korea