Electronic structures of individual poly(3-hexylthiophene) nanowires on hydrogen-terminated Si(100) surfaces

Electronic structures of individual conducting polymers, poly(3-hexylthiophene)s (P3HTs), fixed on a hydrogen-terminated Si(100) surface have been examined by scanning tunneling rnicroscopy/spectroscopy and first-principles calculations within the density-functional approach. The calculations reveal that the electronic structure of the polymer is only weakly influenced by the substrate, which ensures that the fixed polymers maintain a conduction property similar to that of isolated polymers. The current-voltage curves for the substrate-molecule-tip junction show rectification characteristics, indicating the carrier doping in the fixed polymers.