An STM Study of Microscopic Function at the Interface of Organic Films

In order to create an intelligent material, new func tions attributed to an atomic scale structure have been investigated in this experimental study. Systems consisting of thin organic films on inorganic materials have been examined using a scanning tun neling microscope and tunneling spectroscopy. We have found sev eral interesting phenomena such as nonlinear electrical conduction and negative resistance. A negative resistance was observed in the sample of a perylene thin film evaporated on an HOPG substrate by tunneling spectroscopy. This negative resistance is considered to be due to the tunneling current from the STM probe to the sub strate through a discrete energy level of a molecular orbital of the perylene molecule.