A5032226318- Advanced Chemical Physics Studies
- Graphene research and applications
- Catalytic Processes in Materials Science
- Electron and X-Ray Spectroscopy Techniques
- Surface and Thin Film Phenomena
- 2D Materials and Applications
- Semiconductor materials and devices
- Molecular Junctions and Nanostructures
- Carbon Nanotubes in Composites
- Ammonia Synthesis and Nitrogen Reduction
- Catalysis and Oxidation Reactions
- Advancements in Battery Materials
- nanoparticles nucleation surface interactions
- Quantum and electron transport phenomena
- Electronic and Structural Properties of Oxides
- Diamond and Carbon-based Materials Research
- Machine Learning in Materials Science
- X-ray Spectroscopy and Fluorescence Analysis
- Surface Chemistry and Catalysis
- MXene and MAX Phase Materials
- Fullerene Chemistry and Applications
- Boron and Carbon Nanomaterials Research
- Magnetic properties of thin films
- Chalcogenide Semiconductor Thin Films
- Ion-surface interactions and analysis
Elettra-Sincrotrone Trieste S.C.p.A.
2016-2025
Iowa State University
2021
Ames National Laboratory
2021
Aarhus University
2021
Vitenparken
2016
AREA Science Park
1998-2014
Scuola Internazionale Superiore di Studi Avanzati
2007-2009
University of Trieste
1992-2009
University College London
2009
Institute for Complex Systems
2008
We present atomic-scale, video-rate environmental transmission electron microscopy and in situ time-resolved X-ray photoelectron spectroscopy of surface-bound catalytic chemical vapor deposition single-walled carbon nanotubes nanofibers. observe that transition metal catalyst nanoparticles on SiOx support show crystalline lattice fringe contrast high deformability before during nanotube formation. A nucleates by lift-off a cap. Cap stabilization growth involve the dynamic reshaping...
Graphene is easily produced by thermally reducing graphene oxide. However, defect formation in the C network during deoxygenation compromises charge carrier mobility reduced material. Understanding mechanisms of thermal reactions essential for defining alternative routes able to limit density defects generated carbon evolution. Here, we identify a dual path mechanism reduction oxide driven oxygen coverage: at low surface density, O atoms adsorbed as epoxy groups evolve O2 leaving unmodified....
Here, we show that residual contaminants in purified single-wall carbon nanotube bundles may be responsible for the reported sensitivity of electronic and transport properties to oxygen. Removal these makes spectra insensitive O2, CO, H2O, N2, while a strong NO2, SO2, NH3 is observed, confirming possible application nanotubes as powerful sensors capable measuring environmentally significant levels toxic gases.
Using photoemission spectroscopy techniques, we show that oxygen intercalation is achieved on an extended layer of epitaxial graphene Ir(111), which results in the "lifting" and its decoupling from metal substrate. The adsorption below proceeds as clean giving only a slightly higher coverage. Upon lifting, C 1s signal shows downshift binding energy, due to charge transfer oxygen-covered surface. Moreover, characteristic spectral signatures graphene-substrate interaction valence band are...
By combining high-resolution photoelectron spectroscopy and ab initio calculations, we show that carbon nanoislands formed during the growth of a long-range ordered graphene layer on Ir(111) assume peculiar domelike shape. The understanding unusual mechanism these C clusters, which represent an intermediate phase between strongly coupled carbidic quasi-free-standing layer, can provide information for rational design graphenelike systems at nanoscale.
The chemisorption of O atoms on graphite and the thermal reduction oxidized surface were studied by means high energy resolution photoelectron spectroscopy with synchrotron radiation. C 1s core levels valence band spectra used to identify different oxidizing species evaluate extension sp2 conjugation as a function oxidation time annealing temperature. We found that epoxy groups are dominant only at low stage, ethers semiquinones form proceeds. evolution ether/epoxy ratio increasing oxygen...
By using ab initio molecular dynamics calculations, we show that even where the graphene lattice constant contracts, as previously reported for freestanding below room temperature, average carbon-carbon distance increases with in both free and supported graphene. This results a larger corrugation at higher which can affect interaction between supporting substrate. For weakly interacting system graphene/Ir(111), confirm an experimental approach gives direct access to interatomic distances.
Metal-organic coordination interactions are prime candidates for the formation of self-assembled, nanometer-scale periodic networks with room-temperature structural stability. We present X-ray photoelectron spectroscopy measurements such at Cu(100) surface which provide clear evidence genuine metal-organic coordination. This is evident as binding energy shifts in O 1s and Fe 3p peaks, corresponding to atoms involved Our results first charge-transfer surfaces demonstrate a well-defined...
High-quality, large-area epitaxial graphene can be grown on metal surfaces but its transport properties cannot exploited because the electrical conduction is dominated by substrate. Here we insulate Ru(0001) a step-wise intercalation of silicon and oxygen, eventual formation SiO$_2$ layer between metal. We follow reaction steps x-ray photoemission spectroscopy demonstrate insulation using nano-scale multipoint probe technique.
MXenes are a young family of two-dimensional transition metal carbides, nitrides, and carbonitrides with highly controllable structure, composition, surface chemistry to adjust for target applications. Here, we demonstrate the modifications by low-energy ion implantation, leading incorporation Mn ions in Ti3C2Tx (where Tx is termination) thin films. Damage structural defects caused implantation process characterized at different depths XPS on Ti 2p core-level spectra, ToF-SIMS, electron...
We have performed high resolution XPS experiments of the Ru(0001) surface, both clean and covered with well-defined amounts oxygen up to 1 ML coverage. For surface we detected two distinct components in Ru 3d_{5/2} core level spectra, for which a definite assignment was made using Angle-Scan Photoelectron Diffraction approach. p(2x2), p(2x1), (2x2)-3O (1x1)-O structures found peaks are shifted eV higher binding energies. Very good agreement density functional theory calculations these...
We report on a novel approach to determine the relationship between corrugation and thermal stability of epitaxial graphene grown strongly interacting substrate. According our density functional theory calculations, C single layer Re(0001) is corrugated, with buckling 1.6 Å, yielding simulated 1s core level spectrum which in excellent agreement experimental one. found that closely knit network: C-C bond breaking favored buckled regions moiré cell, though it requires presence diffusing vacancies.
The electron-phonon coupling in potassium-doped graphene on Ir(111) is studied via the renormalization of pi* band near Fermi level, using angle-resolved photoemission spectroscopy. found to be fairly weak and almost isotropic, with a mass enhancement parameter lambda= 0.28(6) for both K-M K-G direction. These results are agree well recent first principles calculations.
We present a study on the growth and characterization of high-quality single-layer MoS2 with single orientation, i.e. without presence mirror domains. This orientation layer is established by means x-ray photoelectron diffraction. The high quality evidenced combining scanning tunneling microscopy spectroscopy measurements. Spin- angle-resolved photoemission experiments performed sample revealed complete spin-polarization valence band states near K -K points Brillouin zone. These findings...
Combined fast X-ray photoelectron spectroscopy and density functional theory calculations reveal the presence of two types hydrogen adsorbate structures at graphene/Ir(111) interface, namely, graphane-like islands dimer structures. While former give rise to a periodic pattern, dimers tend destroy periodicity. Our data distinctive growth rates stability both structures, thereby allowing one obtain well-defined patterns clusters. The ability control manipulate formation size on graphene...
We investigate the structure of epitaxially grown hexagonal boron nitride (h-BN) on Ir(111) by chemical vapor deposition borazine. Using photoelectron diffraction spectroscopy, we unambiguously show that a single-domain h-BN monolayer can be synthesized cyclic dose high-purity borazine onto metal substrate at room temperature followed annealing T=1270 K, this method giving rise to pattern with 3-fold symmetry. In contrast, high-temperature (T=1070 K) results in formed domains opposite...
By means of a combination surface-science spectroscopies and theory, we investigate the mechanisms ruling catalytic role epitaxial graphene (Gr) grown on transition-metal substrates for production hydrogen from water. Water decomposition at Gr/metal interface room temperature provides hydrogenated Gr sheet, which is buckled decoupled metal substrate. We evaluate performance as storage medium, with density in sheet comparable state-of-the-art materials (1.42 wt %). Moreover, thermal...
VS2 is a challenging material to prepare stoichiometrically in the bulk, and single layer has not been successfully isolated before now. Here we report first realization of single-layer VS2, which have prepared epitaxially with high quality on Au(1 1 1) octahedral (1T) structure. We find that can deplete lattice S by annealing vacuum so as create an entirely new 2D compound no bulk analogue. The transition reversible upon H2S gas atmosphere. structural properties both stoichiometric...
The nature of bonding in amorphous carbon nitride was studied by synchrotron-radiation photoemission spectroscopy and near-edge x-ray-absorption fine structure. experimental data are compared with theoretical calculations chemical shifts, the relative importance initial final state effects is discussed. Bond lengths determined from position ${\ensuremath{\sigma}}^{*}$ resonance obtained results suggest ${\mathrm{sp}}^{2}$ hybridization. evidence presented this paper supports another...
We show that dissociative oxygen adsorption on Ag(001) induces below room temperature a missing row $2\sqrt{2}\ifmmode\times\else\texttimes\fi{}\sqrt{2}$ reconstruction of the substrate. As demonstrated by analysis photoelectron diffraction patterns, atoms sit thereby in $c(2\ifmmode\times\else\texttimes\fi{}2)$ arrangement previous fourfold hollow sites nearly coplanar with Ag atoms, while rows substrate are removed along $[100]$ directions. Annealing crystal above 350 K restores...