Communications of the ACM
Good Connections to Molecular Electronics
Max Planck researchers from Berlin lift a graphene ribbon from a gold surface with the tip of a scanning tunnelling microscope and investigate how the conductance of the carbon ribbon depends on its length.
Credit: Leonhard Grill/Fritz Haber Institute of the Max Planck Society
Researchers from the Max Planck Society's Fritz Haber Institute have gleaned insights into the optimization of molecular wires from conductance measurements on graphene nanoribbons.
The ribbons were formed by vaporizing molecular snippets of graphene strips onto a surface, and giving the molecules chemical bonds. The conductance of an individual nanowire was measured as a function of its length, which enabled the researchers to determine the functioning of the nanowire's charge transport. This strategy mainly lets the researchers learn if their nanowire is an ideal conductor, and the measurements demonstrated that the current did not flow with relatively low resistance, but rather tunneled through it.
Tunneling is a process exclusive to quantum particles, and the researchers also showed for the first time how the electron energy is essential to the charge transport. The charge transport experiences immediate improvement if they select the electron energy so that it matches the energy of the molecular orbitals. The graphene ribbons are not quite suitable for nanoelectronic applications, but the experiments' finding that the nature of the electron transport hinges on the formation of the edge of the strip points a way toward an optimized nanowire.
From Max Planck Gessellschaft
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