Electronic conductance measurements through a single one-atom thick, few-atom wide planar graphene nanoribbon (GNR) have a lasting interest as GNR hold inherent tunable band gaps relevant to numerous technological applications. For future single-molecule based electronic circuits, the complete electronic components are supposed to be embedded inside one single molecule. Here, atomically precise metallic interconnects connected at both ends of an unperturbed GNR/molecular wire structure with a picometer precision is a difficult experimental and technical problem. To address this issue, our Marie Curie action has explored the low-temperature ultrahigh vacuum (LT-UHV) two-tip scanning tunneling microscopy and spectroscopy (STM and STS) conductance characterization approach. Within the scope of this action, atomically clean conductance characterization of a single GNR in its strictly planar configuration was proposed in a way to override (1) the unclean standard nanolithography-based device fabrication and (2) the actual curved conformation conductance measurement of a single GNR using the STM tip lifting approach. Indeed, a clear understanding of the on-surface GNR synthesis protocol, a detail characterization of the GNR electronic structure stabilization and the characterization of metallic back surface support induced electronic effects have also been achieved through this action. Along the path of this action, we have invented an original and totally UHV compatible way for the measurement of the conductance of a single GNR molecular wire in an exact planar and atomically precise surface configuration, the results of which will be published soon.
