[1] Yonsei Univ, Dept Mat Sci & Engn, Seoul 120749, South Korea
[2] IBM Corp, Div Res, Almaden Res Ctr, San Jose, CA 95120 USA
[3] Seoul Natl Univ, Dept Mat Sci & Engn, Seoul 151749, South Korea
[4] Seoul Natl Univ, Dept Chem, Seoul 151749, South Korea
[5] Yonsei Univ, Dept Chem Engn, Seoul 120749, South Korea
[6] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA