I–V curves of carbon nanotubes with copper contacts using non-equilibrium Green's function method

Using the non-equilibrium Green's function method together with the density-functional theory, the interfaces of carbon nanotubes (CNTs) with Cu electrodes are modeled and the associated I/V curves are evaluated. It is found that the geometry of the interface and electronic transport characteristics are dependent significantly on the diameter of the CNTs. In comparison with the pristine CNT electrode system, the conductance change for the Cu/CNT/Cu system is more sensitive for large diameter CNTs whether the CNT is metallic or semiconductive. The results indicate that the origin is the Cu contacts, which change the electronic structures and the hybridization type of the CNTs due to the C-2pπ and Cu-4s orbital overlaps.

Graphical AbstractConfigurations of the Cu–CNT junctions. Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Geometry of Cu/CNT interface relies on diameter of CNT closely. ► CNT diameter determines rate of conductance change for Cu/CNT/Cu systems. ► Relation between electronic structure and transport properties. ► Mechanism of contact effect from Cu interface.