1. Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-11 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
2. Division of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
3. Department of Electrical and Electronic Engineering, Kobe University, Kobe, Hyogo 657-8501, Japan