Compound polymeric materials in molecular nanodevices: Electrical behavior of zero-dimension semiconducting inorganic molecules embedded in a polymer substrate

Abstract

Several molecular materials are currently being investigated as candidates for nanoelecronic devices with the hope to reduce critical device dimensions to the molecular scale. Possible applications include switching circuits and multilevel memories based on the excitation states of molecules. In this work, we present data about the electrical behavior of two compound materials made by non-conductive poly (methyl methacrylate) (PMMA) or a methacrylate copolymer (PHECIMA) and a certain tungsten polyoxometalate molecule (PW12O 40 - POM), which can be considered as a zero-dimension semiconductor. Certain parameters are examined as variables of the experiments, such as the POM concentration, the material of the electrodes (Al or Au), the inter-electrode separation or the conditions of the preparation of the samples. Conductivity peaks depended on both the concentration of POM and the inter-electrode distance are found at room temperature conditions. Using vertical capacitor structures and thinner films, negative resistance effects are observed. These results can be attributed to multiple tunnelling through a limited number of POM molecules and shows that these systems are actually worth of further investigation. © 2005 IOP Publishing Ltd.