1. Thin Film Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), Yuseong, Daejeon 305-600, Republic of Korea
2. Department of Physics, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu,
Suwon-si, Gyeonggi-do 440-746, Republic of Korea
3. Department of Chemical Engineering
and Materials Science, University of California, Davis, California 95616-5294, United States