Thermally stimulated currents in organic monomolecular layers

Abstract The polarization phenomenon in metal/organic monomolecular layer/metal devices has been studied by thermally stimulated currents (TSCs). The thermal current peaks for various experimental conditions (temperature, electric field, polarization time, dielectric thickness) show that the polarization in orthophenanthroline with three stearic chains is due to local charge displacements between two potential wells. We found that these charge displacements vary as the thickness increases, which implies that the dielectric structure changes when the number of monolayers increases. The high values of the activation energies (1.1–3.4 eV) determined from the current peaks suggest that the moving charges are ions. In orthophenanthroline multilayers at room temperature we have not observed a notable space charge phenomenon due to ion displacements from one electrode to the other.