Fullerene on Nitrogen-Adsorbed Cu(001) Nanopatterned Surfaces: From Preferential Nucleation to Layer-by-Layer Growth

Abstract

Nitrogen (N)-adsorbed Cu(001)-c(2 × 2) nanopatterned surfaces are used as templates to guide the growth of low-dimensional C 60 molecular nanostructures. At room temperature and during the initial stages of growth, C 60 molecules preferentially adsorb on the bare Cu regions on a partially N-covered grid surface. Subsequently, a two-dimensional molecular nanomesh is formed at low (∼0.28 monatomic layer) C 60 coverages. Further deposition leads to C 60 growth on the c(2 × 2)-N surface until the first molecular layer is completed. For a N-saturated surface with trench structures, the <010> steps of these structures serve as initial anchoring sites for C 60 growth. From there, the growth proceeds two-dimensionally until a single C 60 layer is achieved due to island coalescence. In contrast, no nucleation site was observed when the <110> steps were predominant on the surface. At least up to 6 monatomic layers, the growth proceeds layer-by-layer (i.e., the overlayer morphologies are directed by the underlying substrate pattern). Four rotational domains are observed for the quasi-hexagonally close-packed C 60 overlayer with a nearest-neighbor C 60 -C 60 distance of 1.02 nm. It was found that the interaction between C 60 and the c(2 × 2)-N surface is fairly weak, likely dominated by van der Waals forces, whereas the C 60 -Cu interface is chemisorbed. Site-specific electronic effects between these two regions can be resolved by STM even for thick films.

Supramolecular Assemblies Formed on an Epitaxial Graphene Superstructure

“…There are parallels with other systems where molecules or clusters are adsorbed at sites on an ordered array of local potential wells arising from self‐organization due to, for example, surface reconstruction or dislocation arrays,27–29 including those adsorbed on boron nitride15 and graphene monolayers 6. However a distinguishing feature of our work is the observation that the trapping potential is sufficiently compliant to allow the molecules to relax and adopt a local configuration which is controlled by interactions with molecules trapped in neighboring energy minima so that extended, connected structures may be formed.…”

Probing functional self-assembled molecular architectures with solution/solid scanning tunnelling microscopy

“…41 There are two main approaches to device fabrication from organic semiconductors: they can be based on either polymers or small molecules, 42 or sometimes a combination of the two materials types. 43,44 Of these systems, STM is best-suited to probing the characteristics of small molecule films, 45 with ultrahigh vacuum or ambient STM proving useful for vacuumdeposited organic semiconductor thin films, [46][47][48] and solution/ solid STM providing a direct view into the assembly and dynamics that occur in the formation of solution-processed films. In devicerelevant films, which are typically of the order of tens to hundreds of nanometres thick, the bottom film interface is buried and can be difficult to characterize, yet solution/solid STM directly visualises the molecular structure at the interface and can be combined with other techniques to understand how the interface structure affects the overall film morphology.…”

Carbon nanoflake-nanoparticle interface: A comparative study on structure and photoluminescent properties of carbon nanoflakes synthesized on nanostructured gold and carbon by hot filament CVD

“…Moreover, high temperature difference between the filaments and substrate can intensify the diffusion of chemical radicals toward the substrate and thus enhance the nanomaterial growth rate [20]; our experiments have also demonstrated that indeed, the HFCVD technique is quite efficient in synthesizing the hybrid CNFs containing nanomaterials [6,19]. In particular, CH 4 was directly supplied to the CVD chamber without other carrier gas to ensure the fast absorption of CH 4 on the Au/carbon NP, because it benefits the layer-by-layer growth [21]. Furthermore, it was found that the oriented CNFs were grown in HFCVD system which differs from the plasma-enhanced CVD (PECVD) system.…”