Affiliation: | a Information and Electronic Materials Research Laboratory, Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, Republic of Korea b School of Nano and Advanced Materials Engineering, Changwon National University, 9 Sarim-dong, Changwon, Gyoungnam 641-773, Republic of Korea |