Carbon nanomaterials as electrical conductors in electrodes
Abstract: In this project, different molecules have been investigated with the purpose of creating anohmic contact between metals and carbon nano materials. In particular, we considered simplemolecules connecting a graphene layer and a copper-slab. In order to determine the capability of such systems, the electronic structure was computedusing Density Functional Theory (DFT). Structural relaxation was performed in order to findcandidates where the metal and the graphene binds chemically with the hypothesis that thehybridization of the states will induce more states at the Fermi level. Six different molecularchains were tested and three of them were found to chemisorb to the graphene sheet and thecopper surface simultaneously. The electronic properties for these systems were then furtherinvestigated using the density of states (DOS). An overlap density of states (ODOS) wasdefined in order to evaluate the respective contribution of the graphene, metal and molecule. From the DOS analysis, we report that these systems did not form ohmic contacts as the resultshows too few states close to the Fermi level. The most interesting case was using a hexanolchain which had some partially overlapping states seen from the ODOS of the graphenemoleculeand graphene-Cu at the Fermi level. However, these were only small contributions.Further research is crucial in order to find a more suitable molecular chain between thegraphene and the copper for an ohmic contact.
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