Linear chain polymerization initiated by a scanning tunneling microscope tip at designated positions

A conjugated polymer nanowire can be created at any designated position in a monomolecular layer by initiating chain polymerization using a scanning t unneling microscope tip with a spatial precision of the order of 1 nm. The demonstration has been presented for a self-ordered monomolecular layer of 10,12-pentacosadiynoic acid, which is a diacetylene compound, adsorbed on a graphite surface. The polymer nanowires created have a length ranging from 5 to 300 nm, the length being controlled by domain boundaries or artificia l defects in the molecular layer. The frequency of occurrence of chain poly merization is measured against the pulsed bias voltage, which suggests that the excitation of the molecule is caused by the inelastically tunneling el ectrons. (C) 2001 American Institute of Physics.