Publications de Harald Brune | EPFL Graph Search

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We report on low-temperature scanning tunneling microscopy and spectroscopy measurements on NC-Ph-3-CN molecules adsorbed at 300 K on a Cu(111) surface. Upon cooling, the molecules form chain and honeycomb structures, incorporating Cu adatoms supplied by t ...

In the present article we describe a new setup for an atomic force microscope in the beetle-type geometry. The microscope consists of a compact head standing on three piezo legs with a fourth central piezo carrying the cantilever tip. We use the laser beam deflection method to detect the deflection of the cantilever. All optical components are integrated into the microscope head which has a diameter of 40 mm. This compactness results in a high mechanical stability, while the adjustment of the optical pathwa

We report on the strengths and limitations of scanning tunnelling microscopy (STM) when used for characterising atomic-scale features of quasi two-dimensional materials, such as graphene and single layers of hexagonal boron nitride, which may present stron ...

The catalytic activity of deposited Pt-7 clusters has been studied as a function of the reduction state of the TiO2(110)-(1 x 1) support for the CO oxidation reaction. While a slightly reduced support gives rise to a high catalytic activity of the adpartic ...

We investigate the effects of Na adsorption on the electronic structure of bare and Ir cluster superlattice-covered epitaxial graphene on Ir(111) using angleresolved photoemission spectroscopy and scanning tunneling microscopy. At Na saturation coverage, a massive charge migration from sodium atoms to graphene raises the graphene Fermi level by ∼1.4 eV relative to its neutrality point. We find that Na is adsorbed on top of the graphene layer, and when coadsorbed onto an Ir cluster superlattice, it results i

Based on kinetic Monte Carlo simulations, we show that modulated wires and island gratings can be formed at vicinal surfaces. The modulation (grating) wavelength along the steps can be tailored by external conditions (coverage and temperature) and intrinsic surface properties (diffusion, terrace width) via a scaling law. Above 220 K a thermodynamic saturation value for the wavelength occurs, which depends only on the terrace width. This morphological behavior can be understood in terms of nucleation argumen

We report on a multi-technique investigation of the supramolecular organisation of N,N-diphenyl oxalic amide under differently dimensioned environments, namely three-dimensional (3D) in the bulk crystal, and in two dimensions on the Ag(111) surface as well ...

We have used variable-temperature scanning tunneling microscopy to study the aggregation of two-dimensional Ag clusters on Pt(111). A transition from randomly ramified to dendritic fractal growth is observed in the diffusion-limited regime. Atomic-scale observations have identified the anisotropy of edge diffusion as microscopic origin of this crossover. Dependent on the deposition flux, this anisotropy is either amplified to the macroscopic-cluster shape and trigonal dendrites result, or it is degenerated

The influence of strain on diffusion and nucleation has been studied by means of scanning tunneling microscopy and effective-medium theory for Ag self-diffusion on strained and unstrained (111) surfaces. Experimentally, the diffusion barrier is observed to be substantially lower on a pseudomorphic Ag monolayer on Pt(111), 60 meV, compared to that on Ag(111), 97 meV. The calculations show that this strong effect is due to the 4.2% compressive strain of the Ag monolayer on Pt. It is shown that in general isot

We derive an analytical expression for the size distribution of monoatomic wires in the framework of a one-dimensional lattice gas model at thermodynamic equilibrium. The theoretical results are compared with the size distribution of one-dimensional Ag wir ...

We present a comprehensive study of the magnetism and morphology of an ultrahigh density array of Co nanoclusters self-assembled on the single atomic layer GdAu2 on Au(111) template surface. Combining scanning tunneling microscopy, x-ray magnetic circular ...

We present a novel method for the fabrication of well-ordered, two-dimensional nanocluster arrays. The method is based on the confined nucleation of adatoms within the superstructure cells of periodic surface dislocation networks, which form in many heteroepitaxial systems. Sire show how quantitative understanding of adatom diffusion and heterogeneous nucleation on such surfaces can be obtained through kinetic Monte-Carlo simulations and discuss the potential of this approach.

The velocity and humidity dependence of nanoscopic sliding friction has been studied on CrN and diamondlike carbon surfaces with an atomic force microscope. The surface wettability is found to be decisive. Partially hydrophilic surfaces show a logarithmic decrease of friction with increasing velocity, the slope of which varies drastically with humidity, whereas on partially hydrophobic surfaces we confirm the formerly reported logarithmic increase. A model for the thermally activated nucleation of water bri

Variable-temperature scanning tunneling microscopy was used to study the effect of kinetic cluster energy and rare-gas buffer layers on the deposition process of size-selected silver nanoclusters on a platinum(111) surface. Clusters with impact energies of ...

TbPc2 single-molecule magnets adsorbed on a magnesium oxide tunnel barrier exhibit record magnetic remanence, record hysteresis opening, perfect out-of-plane alignment of the magnetic easy axes, and self-assembly into a well-ordered layer.

Scanning capacitance microscopy and electrostatic force microscopy have been used to characterize commercial semiconductor devices at various stages of the fabrication process. These methods, combined with conventional atomic force microscopy, allow to visualize qualitatively the oxide thickness, the nature of dopants and the exact position of implanted areas. (C) 2002 Elsevier Science Ltd. All rights reserved.

We report an experimental and a theoretical study of the radial elasticity of multiwalled carbon nanotubes as a function of external radius. We use atomic force microscopy and apply small indentation amplitudes in order to stay in the linear elasticity reg ...

The ordering of two-dimensional Ag islands embedded in the Pt(111) surface layer has been investigated using He-atom scattering and scanning tunneling microscopy. At lower Ag coverage the embedded islands consist of compact clusters (disks) arranged into a short-range ordered two-dimensional array. At higher coverage the Ag islands have an elongated shape leading to a ''labyrinthine'' pattern of regularly spaced meandering stripes. As the temperature is increased, both the disk and stripe arrays of embedded

We report a quantitative atomic scale study of nucleation kinetics on an inhomogeneous substrate. Our model system, Al/Au(111)-(root 3 x 22), reveals a distinct nucleation transition due to the repulsive nature of surface dislocations. Whereas for T < 200 K Al adatoms are confined to quasipseudomorphic stacking areas experiencing a very small diffusion barrier (30 +/- 5 meV), at T > 200 K surface dislocations, representing repulsive barriers of Delta E approximate to 560 meV, can be surmounted. The results

Harald Brune

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Isolated Pd Sites on the Intermetallic PdGa(111) and PdGa($\bar 1$ $\bar 1$ $\bar 1$) Model Catalyst Surfaces

Competing Interactions in the Self-Assembly of NC-Ph-3-CN Molecules on Cu(111)

Design of a ''beetle-type'' atomic force microscope using the beam deflection technique

Giant apparent lattice distortions in STM images of corrugated sp2-hybridised monolayers

Effect of the TiO2 Reduction State on the Catalytic CO Oxidation on Deposited Size-Selected Pt Clusters

Large Band Gap Opening between Graphene Dirac Cones Induced by Na Adsorption onto an Ir Superlattice

Grating formation in step flow heterogeneous growth and wavelength selection induced by confinement

Does the Surface Matter? Hydrogen-Bonded Chain Formation of an Oxalic Amide Derivative in a Two- and Three-Dimensional Environment

Aggregation of Fractal and Dendritic Ag Clusters on a Pt(111) Surface

Effect of Strain on Surface-Diffusion and Nucleation

Equilibrium island-size distribution in one dimension

Magnetism and morphology of Co nanocluster superlattices on GdAu2/Au(111)-(13 x 13)

Self-organized growth of cluster arrays

Kinetics of capillary condensation in nanoscopic sliding friction

Controlled deposition of size-selected silver nanoclusters

Giant Hysteresis of Single-Molecule Magnets Adsorbed on a Nonmagnetic Insulator

Use of scanning capacitance microscopy for controlling wafer processing

Radial elasticity of multiwalled carbon nanotubes

Stability of Disk and Stripe Patterns of Nanostructures at Surfaces

Nucleation kinetics on inhomogeneous substrates: Al/Au(111)