Journal of Electron Spectroscopy and Related Phenomena最新文献

The spatially resolved ARPES (nanoARPES) is a development of conventional ARPES technique achieved with the focusing of light on the sample into the spot with submicron sizes. This development is used in research of essentially small samples, for example, heterostructures build of flakes of 2D materials, micro-crystals or polycrystalline samples, different crystal termination, domains in electronic structure. ANTARES is delivering the nanoARPES technique to user community since 2010, up to now the instrument was used with samples of various types, and that was useful to accumulate the specific experience. In this paper we report the current layout and actual performance of the ANTARES instrument at Synchrotron SOLEIL, as well as the most typical application areas. The most important and recent upgrades include focusing optics and in-operando setup. The new optical units deliver the increased flux on sample as well as the option to vary the photon energy. The in-operando setup offers the option of electrical connection to the sample being studied with nanoARPES, that promises various applications, where the most demanded now is the control of charge carrier density with applied voltage. This “gate-doping” is often applied to the heterostructures of 2D materials, that could be designed and build on purpose. The 2D heterostructures is probably the most typical field of application of the instrument, with or without in-operando option. At the same time the use case of the ANTARES instrument is still in the development by the realisation of new kinds of samples and of the new types of the experiments.

The development of advanced energy systems is essential for replacing fossil fuel-based societies, and progress in the fundamental understanding of solid-state energy materials has revolutionized this field. In particular, investigating the inhomogeneity of reactions in energy systems requires analysis at the level of individual particles, which are the smallest units in the system. Synchrotron-based scanning transmission X-ray microscopy (STXM) is a valuable tool for exploring reaction and degradation mechanisms, and providing nanoscale site-specific information on chemical and structural changes within single particles. In-situ/operando STXM is particularly useful for observing reactions under well-controlled conditions in real time, thus providing insights into local phenomena obscured by the ensemble effect. This review highlights the research achievements of in-situ/operando STXM in the field of energy materials and provides perspectives for advanced X-ray imaging techniques that can further enhance STXM capabilities.

With size reduction of active elements in microelectronics to tens of nanometers and below, the effect of surface and interface properties on overall device performance becomes crucial. High resolution spectroscopic and imaging techniques provide a metrological route for characterization of these properties relevant to device diagnostics and failure analysis. With its roughly 100 nm spatial resolution, superior surface sensitivity, and approximately 200 meV spectral resolution, scanning photoelectron microscopy (SPEM) stands out as a comprehensive tool to access the surface/interface composition of nanodevices, as well to provide chemical state designations and materials property evolutions upon treatment by thermal, electrical, chemical, radiative and other stimuli. Here we present a SPEM-on-device setup that combines X-ray spectromicroscopy with advanced NIST microhotplate technology to demonstrate new combined analytical and electrical measurements capabilities of this metrology platform for operando nanodevice characterization. Using model integrated SnO₂ nanowire (NW) chemiresistor devices, the chemically induced alterations in the chemical state of the nanowire surface are correlated to the observed conductance changes, thus directly testing the receptor and transduction mechanisms for SnO₂ NW conductometric chemical sensors.

Microscopy using the soft X-ray as an illumination source can integrate spectroscopy into images. This capability was implemented at Taiwan Light Source (TLS) in the early 2000s through two photoelectron-based microscopy stations whose imaging optics is either zone-plate (TLS 09A1) or electron lens (TLS 05B2). The microscopy project was later expanded into multiple stations and beamlines at Taiwan Photon Source (TPS) to take advantage of TPS’s low emittance. In this report, we summarize the activities of soft X-ray microscopy at TLS, followed by the status of microscopy stations under construction at beamline TPS 27A and 39A. The new lineup at TPS is to meet the scientific challenges ahead while carrying the existing activities forward. Both photoemission and transmission X-ray microscopy will be available at TPS.

We review the main developments and first commissioning experiments at the CARNAÚBA X-ray nanoprobe beamline, recently installed at the brand-new Sirius 4th-generation synchrotron radiation source at the Brazilian Synchrotron Light Laboratory (LNLS). The paper briefly discusses the X-ray nanoprobe instrument, emphasizing the first deployed experimental station TARUMÃ, and showcases preliminary results in a broad range of areas that benefit from diverse sample environments. Research domains like photovoltaics, photonics, electrocatalysis, geoscience, and agriculture are investigated from the viewpoint of chemistry, atomic structure, morphology, and redox dynamics phenomena covered by the beamline techniques. Finally, future capabilities are presented based on a new instrument under development.

Synchrontron radiation enabled recent measurement of the complete photoemission spectrum of acrylamide reported by Evangelisti et al. in Photochem. 2 (2022) 463. It seems to be a pity that calculation with the usually reliable ab initio method SAC-CI did not produce good agreement with experiment. In the present study, we use density functional theory methods in order to improve the agreement between experiment and theory. Such agreement helps to validate the DFT methods used. Our DFT results also suggest that two peaks in the N1s X-ray absorptiom spectrum have been incorrectly assigned.

Single crystalline LiFe_0.6Mn_0.4PO₄ (LFMP) nanowires with carbon sheath were analyzed by scanning transmission X-ray microscopy (STXM) with a spatial resolution of around 130 nm. The pinpoint Fe L-edge X-ray absorption spectroscopy (XAS) spectra in the STXM images revealed the natural oxidation of Fe²⁺ to Fe³⁺ near the tip of the nanowire by air exposure. The pinpoint O K-edge XAS spectra simultaneously changed with the Fe L-edge XAS in the STXM mapping because of the hybridization between the O 2p and Fe 3d orbitals. On the other hand, the Mn L-edge XAS spectra showed an almost uniform Mn²⁺ state all over the nanowires, suggesting that the Mn²⁺ state is stable against the natural oxidation in contrast to the Fe²⁺ state. We have thus demonstrated that STXM is a useful technique to visualize oxidized areas of materials and to reveal detailed information about their electronic structure.

In this work, the saddle-point variation combined with complex-rotation methods are used to calculate term energies, radiative transition wavelengths and Auger transition energies of the 1s2s²2p² (²S, ²P, ²D, ⁴P), 1s2s²2p3p (²S, ²P, ²D), 1s2s2p³ (^2,4S°, ^2,4P°, ^2,4D°), and 1s2p⁴ (²S, ²P, ²D, ⁴P) resonances for F⁴⁺. The present term energies, radiative rates, radiative transition wavelengths, Auger rates and corresponding transition energies agree well with the multiconfiguration Dirac-Fock calculation results listed in the literature. Other transition data in this work are expected to offer reference values for future studies.

CO₂ electrochemical reduction (CO₂ER) is a promising technology that can convert CO₂ into useful chemicals and fuels with simultaneously reducing greenhouse gas emissions. Cu nanoparticles-based catalysts are an optimal choice of CO₂ER due to its excellent conductivity and catalytic activity. In this study, we combined scanning transmission X-ray microscopy (STXM) and spectro-ptychography to investigate the chemical and electronic structural changes of the CuAg nanocatalysts before and after CO₂ER. We observed that Cu species with the same valence state self-aggregate into separated phases. For the spent CuAg nanocatalysts after CO₂ER, most Cu(I) and Cu(0) species are oxidized to Cu(II) together with CuO transforming into undetermined Cu(II) species. We believe these mechanisms are the key reason why the CuAg nanocatalysts lost catalytic activity. Such information will be highly valuable for understanding Cu nanoparticles catalyzed CO₂ER.