1. Organic Electronics Laboratory, Division of Materials Science, Nara Institute of Science and Technology, Takayama-cho 8916-5, Ikoma-shi 630-0196 Japan
2. Green Electronics Division, Graduate School of LSSE, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu-shi 8080196 Japan