Scanning tunneling microscopy and X-ray spectroscopy measurements are combined to first-principles simulations to investigate the formation of graphene nanoribbons (GNRs) on Au(110), as based on the surface-mediated reaction of 10,10′-dibromo-9,9′-bianthracene (DBBA) molecules. At variance with Au(111), two different pathways are identified for the GNR self-assembly on Au(110), as controlled by both the adsorption temperature and the surface coverage of the DBBA molecular precursors. Room-temperature DBBA deposition on Au(110) leads to the same reaction steps obtained on Au(111), even though with lower activation temperatures. For DBBA deposition at 470 K, the cyclodehydrogenation of the precursors preceds their polymerization, and the GNR formation is fostered by increasing the surface coverage. While the initial stages of the reaction are found to crucially determine the final configuration and orientation of the GNRs, the molecular diffusion is found to limit in both cases the formation of high-density long-range ordered GNRs. Overall, the direct comparison between the Au(110) and Au(111) surfaces unveils the delicate interplay among the different factors driving the growth of GNRs

Ultrathin ordered films of TiO x (x ≈ 1) on Pt(111) have been investigated by scanning tunneling microscopy (STM) to test their capability as templates for growing ordered and monodispersed Au nanocluster arrays. The ordered array of parallel black troughs spaced by 1.44 nm, observed in the STM data of the zigzag-like TiO x ultrathin film, was revealed to be a good template for growing a linear array of Au clusters, with a mean size of 1.3 nm and a narrow dispersion. The wagon-wheel-like TiO x film, having a similar chemical composition but without a nanostructured array of defects, does not show templating effects, thus leading to nucleation of disordered and larger Au clusters (mean size of 3.4 nm with a large dispersion). Hence, this work shows that the ordering of the deposited Au nanoclusters is strongly dependent on the actual defectivity of the film. Annealing the Au cluster arrays at high temperature produces drastic changes in the spatial arrangement of the clusters, which has been interpreted as the consequence of the changes in the ultrathin film template.

The morphological and mechanical properties of nanoparticles-based ultrathin Ag films, synthesized by supersonic cluster beam deposition over a sapphire substrate, are unveiled exploiting ultrafast optoacoustic, atomic force microscopy, Xray photoelectron spectroscopies, and X-ray diffraction techniques. The films, with thicknesses in the 10−50 nm range, have a porous structure composed of metallic Ag nanoparticles with a crystalline structure and average diameter of 6 nm. The films acoustic modes are in the hypersonic frequency range, the thinner films frequencies exceeding 100 GHz. The acoustic spectra are well accounted for modeling the nanoparticles film as an effective continuous medium. The modes quality factors show the existence of acoustically quasi-dark and bright states. The film effective density and effective elastic stiffness constants are respectively 0.8 and 0.5 that of bulk Ag. The present results are relevant in view of applications for optoacoustic transducers in the hypersonic frequency range, for optical coatings technology and for the production of mechanically stable bactericidal coatings.

Ultrathin metal nanoparticles coatings, synthesized by gas-phase deposition, are emerging as go-to materials in a variety of fields ranging from pathogens control and sensing to energy storage. Predicting their morphology and mechanical properties beyond a trial-and-error approach is a crucial issue limiting their exploitation in real-life applications. The morphology and mechanical properties of Ag nanoparticle ultrathin films, synthesized by supersonic cluster beam deposition, are here assessed adopting a bottom-up, multitechnique approach. A virtual film model is proposed merging high resolution scanning transmission electron microscopy, supersonic cluster beam dynamics, and molecular dynamics simulations. The model is validated against mechanical nanometrology measurements and is readily extendable to metals other than Ag. The virtual film is shown to be a flexible and reliable predictive tool to access morphology-dependent properties such as mesoscale gas-dynamics and elasticity of ultrathin films synthesized by gas-phase deposition.

The competition between rectangular and hexagonal phases in TiO x ultrathin (monolayer) films grown on a Pt(111) surface is discussed and rationalized on the basis of general building principles for these pseudoepitaxial oxide phases on a (111) metal substrate. A novel hexagonal reduced phase is also presented for the first time, obtained by thermal treatment at high temperature (∼1000 K), and its atomistic structure is unveiled through a combination of STM experiments and theoretical simulations. A consistent picture is obtained for a class of structural families for ultrathin oxide phases on close-packed single-crystal metal surfaces.

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The emerging fields of graphene-based magnetic and spintronic devices require a deep understanding of the interface between graphene and ferromagnetic metals. This paper reports a detailed investigation at the nanometer level of the Fe-graphene interface carried out by angle-resolved photoemission, high-resolution photoemission from core levels, near edge X-ray absorption fine structure, scanning tunnelling microscopy and spin polarized density functional theory calculations. Quasi-free-standing graphene was grown on Pt(111), and the iron film was either deposited atop or intercalated beneath graphene. Calculations and experimental results show that iron strongly modifies the graphene band structure and lifts its π band spin degeneracy.

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