1. BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, Display Device and Processing Laboratory, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea, and Analytic Engineering Center, Samsung Advanced Institute of Technology, P.O. Box 111 Suwon, 440-600, Republic of Korea