C58 on Au(111): A scanning tunneling microscopy study

Abstract

C58 fullerenes were adsorbed onto room temperature Au(111) surface by low-energy (~6 eV) cluster ion beam deposition under ultrahigh vacuum conditions. The topographic and electronic properties of the deposits were monitored by means of scanning tunnelling microscopy (STM at 4.2 K). Topographic images reveal that at low coverages fullerene cages are pinned by point dislocation defects on the herringbone reconstructed gold terraces (as well as by step edges). At intermediate coverages, pinned monomers act as nucleation centres for the formation of oligomeric C58 chains and 2D islands. At the largest coverages studied, the surface becomes covered by 3D interlinked C58 cages. STM topographic images of pinned single adsorbates are essentially featureless. The corresponding local densities of states are consistent with strong cage-substrate interactions. Topographic images of [C58]n oligomers show a stripe-like intensity pattern oriented perpendicular to the axis connecting the cage centers. This striped pattern becomes even more pronounced in maps of the local density of states. As supported by density functional theory, DFT calculations, and also by analogous STM images previously obtained for C60 polymers [M. Nakaya, Y. Kuwahara, M. Aono, and T. Nakayama, J. Nanosci. Nanotechnol. 11, 2829 (2011)], we conclude that these striped orbital patterns are a fingerprint of covalent intercage bonds. For thick C58 films we have derived a bandgap of 1.2 eV from scanning tunnelling spectroscopy data confirming that the outermost C58 layer behaves as a wide band semiconductor.

Ab initioquantum transport through armchair graphene nanoribbons: Streamlines in the current density

“…Indeed, consider recent STM experiments on the fullerenes C 58 and C 60 . 50,51 For a single fullerene, (low bias) STM images show an structureless circular spot, roughly consistent with the absence of the analogue of hard-wall boundary conditions -roughly similar to (zigzag) carbon nanotubes discussed above. Boundary conditions removing the rotational symmetry are realized with a formation of a chemical bond between two different fullerene cages.…”

Soft‐ and reactive landing of ions onto surfaces: Concepts and applications

“…Highly oriented pyrolytic graphite (HOPG) is an atomically flat substrate ideally suited for imaging soft‐landed ions using atomic force microscopy (AFM) and scanning tunneling microscopy (STM) (Bottcher et al, , ). Crystalline metal surfaces with atomically flat terraces including Cu(001) (Thontasen et al, ; Deng et al, ; Kahle et al, ), Au(111) (Deng et al, ; Kahle et al, ; Bajales et al, ; Hauptmann et al, , ), and Ag(111) (Hauptmann et al, ) have also been used for high‐resolution microscopy of soft landed ions. While preparation of clean flat metal surfaces requires specialized UHV instrumentation and repeated cycles of sputtering and annealing, clean HOPG surfaces are readily obtained by cleaving the top layer of the substrates using the “scotch‐tape” method prior to soft‐landing.…”

“…Reactive‐landing of C 58 + ions onto atomically flat gold surfaces has been shown to enable direct visualization of the individual steps of the formation of fullerene films using STM while the electronic structure of the clusters was characterized employing STS (Bajales et al, ). The initial stages of film growth involve pinning of the clusters at surface defect sites at low coverage.…”

“…STM topographic image and height profile of a C 58 aggregate and the experimentally measured (middle) as well as theoretically calculated (right) spatial distribution of HOMO and LUMO‐states for the C 58 aggregate. Adapted from Bajales et al ().…”

DRILL Interface Makes Ion Soft Landing Broadly Accessible for Energy Science and Applications

“…Soft landing (SL) of ions onto surfaces is a versatile approach for precisely‐controlled preparation of materials for applications and fundamental research in materials, physics, chemistry, and biology . Recent reports have demonstrated the use of SL for preparation of well‐defined model catalysts through deposition of mass‐selected clusters, nanoparticles, and organometallics . SL also has been used to deliver nanoparticles to tissue where they serve as an ionization enhancing matrix for mass spectrometry imaging .…”