Scanning Photoelectron Spectro‐Microscopy: A Modern Tool for the Study of Materials at the Nanoscale

Zeller, Patrick; Amati, Matteo; Sezen, Hikmet; Scardamaglia, Mattia; Struzzi, Claudia; Bittencourt, Carla; Lantz, Gabriel; Hajlaoui, Mahdi; Papalazarou, E.; Marsi, M.; Fanetti, Mattia; Ambrosini, Stefano; Rubini, S.; Gregoratti, Luca

doi:10.1002/pssa.201800308

Cited by 15 publications

(14 citation statements)

References 39 publications

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“…the whole image takes below 5 min, while the high-resolution Rh 3d or O 1 s spectra take less than 1 min. The overall energy resolution is 0.3 eV 50 . Due to the setup geometry, electrons emitted at an angle of 60° to the surface normal were registered.…”

Section: Methodsmentioning

confidence: 99%

Coexisting multi-states in catalytic hydrogen oxidation on rhodium

et al. 2021

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Catalytic hydrogen oxidation on a polycrystalline rhodium foil used as a surface structure library is studied by scanning photoelectron microscopy (SPEM) in the 10−6 mbar pressure range, yielding spatially resolved X-ray photoemission spectroscopy (XPS) measurements. Here we report an observation of a previously unknown coexistence of four different states on adjacent differently oriented domains of the same Rh sample at the exactly same conditions. A catalytically active steady state, a catalytically inactive steady state and multifrequential oscillating states are simultaneously observed. Our results thus demonstrate the general possibility of multi-states in a catalytic reaction. This highly unusual behaviour is explained on the basis of peculiarities of the formation and depletion of subsurface oxygen on differently structured Rh surfaces. The experimental findings are supported by mean-field micro-kinetic modelling. The present observations raise the interdisciplinary question of how self-organising dynamic processes in a heterogeneous system are influenced by the permeability of the borders confining the adjacent regions.

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Section: Methodsmentioning

confidence: 99%

Coexisting multi-states in catalytic hydrogen oxidation on rhodium

et al. 2021

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“…After NW dispersion onto a Si substrate, sample S2 was rapidly sealed into the UHV chamber of the ANTARES beamline at synchrotron SOLEIL . It should be noted that SPEM experiments could also be performed on vertical NW grown on their original substrate; , however, we dispersed the NWs on a substrate to measure individual NWs. Figure a shows the XPS spectrum of sample S2 acquired with large spot size.…”

Section: Resultsmentioning

confidence: 99%

Insights into the Arsenic Shell Decapping Mechanisms in As/GaAs Nanowires by X-ray and Electron Microscopy

et al. 2021

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Nanowire heterostructures of the oxide (shell)–semiconducting (core) type are of interest for various applications in energy harvesting, such as electrodes for photocatalysis and in sensors. Their complete synthesis often requires the deposition of the shell and the core in two separate reactors, with the risk of exposing the core to oxidation from atmospheric conditions during transfer. Here, we study the desorption mechanisms and protection efficiency of an arsenic shell, which was purposely deposited on the GaAs core for protection against undesirable oxidation. Using in situ heating in transmission electron microscopy and synchrotron radiation scanning photoelectron microscopy, we explore the morphology, structure, and surface chemistry of GaAs nanowires capped with an arsenic shell, from room temperature to 500 °C. A phase transformation from amorphous to polycrystalline arsenic is evidenced at a temperature of about 300 °C, alongside the disappearance of the surface oxidation observed at room temperature. At higher temperatures, the arsenic shell desorbs with an activation energy of 2.32 eV, leading to clean facets. These results are helpful to determine pathways toward improving the efficiency of oxidation-protective layers on III–V semiconducting nanostructures.

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“…The scanning photoelectron microscope (SPEM) allows spatially resolved XPS measurements in the submicron scale [ 32 , 33 ]. SPEM measurements were performed by using the Escamicroscopy beamline at Elettra synchrotron facility (Trieste, Italy).…”

Section: Methodsmentioning

confidence: 99%

Graphene Coating Obtained in a Cold-Wall CVD Process on the Co-Cr Alloy (L-605) for Medical Applications

Wasyluk

Boiko

Markowska

et al. 2021

IJMS

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Graphene coating on the cobalt-chromium alloy was optimized and successfully carried out by a cold-wall chemical vapor deposition (CW-CVD) method. A uniform layer of graphene for a large area of the Co-Cr alloy (discs of 10 mm diameter) was confirmed by Raman mapping coated area and analyzing specific G and 2D bands; in particular, the intensity ratio and the number of layers were calculated. The effect of the CW-CVD process on the microstructure and the morphology of the Co-Cr surface was investigated by scanning X-ray photoelectron microscope (SPEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Nanoindentation and scratch tests were performed to determine mechanical properties of Co-Cr disks. The results of microbiological tests indicate that the studied Co-Cr alloys covered with a graphene layer did not show a pro-coagulant effect. The obtained results confirm the possibility of using the developed coating method in medical applications, in particular in the field of cardiovascular diseases.

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Scanning Photoelectron Spectro‐Microscopy: A Modern Tool for the Study of Materials at the Nanoscale

Cited by 15 publications

References 39 publications

Coexisting multi-states in catalytic hydrogen oxidation on rhodium

Coexisting multi-states in catalytic hydrogen oxidation on rhodium

Insights into the Arsenic Shell Decapping Mechanisms in As/GaAs Nanowires by X-ray and Electron Microscopy

Graphene Coating Obtained in a Cold-Wall CVD Process on the Co-Cr Alloy (L-605) for Medical Applications

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