We developed a full-field X-ray diffraction (FFXRD) imaging method using a straight polycapillary realized in the laboratory that can obtain X-ray diffraction (XRD) images with a large area in a short time throughout the simple process without the synchrotron radiation facility. The FFXRD imaging instrument can obtain the XRD images of several millimeter sizes in several hundreds of seconds at each lattice plane. The positional resolution and the spatial resolution was improved by using a straight polycapillary with long type. The FFXRD imaging instrument was attached to the heat treatment system and Cu plate was heat-treated at 300°C. As an example of in situ monitoring of the change in the crystal structure distribution, a high-temperature oxidation process of Cu was observed. The XRD images of Cu, Cu₂O, and CuO at each lattice plane were obtained every hour. While the crystal structure distribution of Cu was reduced, the crystal structure distribution of Cu₂O and CuO were increased with the oxidation process of Cu by the heat treatment. The change of the crystal structure distribution near the surface by the oxidation process of Cu was confirmed. The XRD image obtained by the FFXRD imaging instrument was analyzed by micro-XRD measurements and confirmed that the FFXRD imaging instrument can accurately obtain the crystal structure distribution. In order to obtain the XRD image with a large area, the FFXRD imaging instrument that can be realized in the laboratory has advantages regarding the exposure time of X-rays and in situ analysis.

Direct Ga-doping into ZnO nanoparticles (NPs) were tried by thermal treatment mixed with Ga₂O₃ particles. Residual Ga₂O₃ particles were completely removed by appropriate centrifugation process. To confirm the Ga-doping, variations of sheet resistances for sprayed NP-layers on glass substrates were investigated, showing successful and dramatic reduction from GΩ sq⁻¹-order to sub-kΩ sq⁻¹. The minimum sheet resistance reached to 225 Ωsq⁻¹. From X-ray diffraction and X-ray photoelectron spectroscopy analyses, it can be concluded that Ga atoms diffused from Ga₂O₃ into ZnO-NPs in the thermal treatment process, and some of them substituted for Zn atoms and were activated as donors. These results can contribute to continuous advance of ZnO-NP-based thin-film-transistor fabrication technique.

Orthorhombic-type sodium tantalite (NaTaO₃) is one of the most promising photocatalyst for hydrogen generation via water splitting reaction with ultraviolet-irradiation. In this research, we prepared NaTaO₃ crystal from KTaO₃ substrate via solid-state K⁺−Na⁺ alkaline cation substitution. In the transmission electron microscopy (TEM) observation revealed the perovskite-type KTaO₃ crystal phase is transformed into the orthorhombic crystal phase via simple heating of KTaO₃ substrate with Na₂O₂. Atomic scale scanning TEM imaging with energy dispersive X-ray spectroscopy (EDS) are supported that this phase transformation clearly based on the topotactic alkaline cation substitution with K⁺ and Na⁺ at a common Ta-O basic lattice structure.

The article describes a new method of organosilicon compounds activation by low energy electron beam for SiCN coatings deposition. The composition of the beam plasma in a hexamethyldisilazane-containing gas medium was studied, and it was shown that the precursor molecules decomposition degree increases with the beam current and nonmonotonically depends on the electron beam energy. The application of a low-energy electron beam for the plasma-chemical vapor decomposition of hexamethyldisilazane and for samples heating up by electron beam to 600°C makes it possible to obtain SiCN-based coatings with a hardness up to 18 GPa and thickness ∼1 μm for 1 h.

Electrical transmission overhead lines use an aluminum conductor in services. However, protection of the aluminum conductor from corrosion has to be considered. Hence, an extensive experimental work was done to prepare the composite coating of the aluminum conductor. Three types of polyurethane composites were fabricated with different fillers (5 wt% carbon and 5 wt% organoclay) and were characterized. The composites were polyurethane/carbon (PC), polyurethane/organoclay (PClay), and polyurethane/carbon/organoclay (PCClay). Thermogravimetry analysis and Fourier transform infrared spectroscopy were conducted to obtain thermal properties and chemical bonding of the composites. To obtain the corrosion resistance, salt spray tests were applied. To obtain hydrophobicity properties, the contact angle between water and the composites was measured. Measurements of composites relative permittivity was conducted to obtain dielectric properties. A water vapor permeability test was conducted to obtain the rate of water/gas vapor discharge. Finally, an adhesion test was conducted to obtain adhesion performance according to the ASTM D3359 standard. Based on characterization, PCClay had better characters to be used as an overhead aluminum coating material followed by PC and PClay.

Porous ZnO micron powders are obtained by thermal oxidation in air. The as-obtained powders are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption, and ultraviolet-visible spectrophotometer, and the photocatalytic degradation of methyl orange (MO) is evaluated. The results indicate that, with the increase in thermal oxidation temperature, the nanoparticles on the surface of porous ZnO gradually grow and connect to each other, and the porous structure is destroyed, which results in the decrease in the specific surface area. Porous ZnO obtained at 800°C exhibits the best photocatalytic performance for MO degradation. The highest degradation rate is 0.043 min⁻¹ using 10 mg of the ZnO powders and 10 mg L⁻¹ of the MO solution.

The paper reports results of a systematic investigation of electric field effects on residual H signals in atom probe analysis. Three species, H⁺, H₂⁺, and H₃⁺, can be detected on a Pt surface without gas introduction into the ultra-high vacuum chamber. The H⁺ ions are more likely to be detected at a higher electric field. On the other hand, the H₂⁺ and H₃⁺ ions appear at the lower electric field. A comparison of residual H and a D₂ gas confirmed that residual H is in the H₂ gas form. H₂ can be dissociated to H on the Pt surface. Consequently, H, H₂, and H₃ coexist on the Pt surface and desorb at an appropriate electric field.

The hydrogen content x of Nb hydrides, NbH_x and/or NbD_x, formed in supercritical water under extremely high pressures and temperatures were studied as a function of the depth from the hydride surface via ion-beam analyses (elastic recoil detection analysis with Rutherford backscattering spectrometry, ERDA/RBS). The hydrogen-rich α'-NbH (x ≈ 0.9) formed a surface layer approximately 200-nm thick with a 4−25 nm Nb oxide overlayer, which was invisible or only barely visible in the X-ray diffraction (XRD) analysis, whereas the hydrogen-poor α-NbH (x < 0.2) was visible to a depth of 1 μm in the bulk. The oxide overlayer thickened with further hydrogenation. The exchange of D with H was suggested in the surface region for the hydride specimen formed with D₂O. The chemical states of the studied specimens were also analyzed via the angle-dependent hard X-ray photoelectron spectroscopy, HAXPES. The formation mechanism of Nb hydrides is discussed based on the depth profiles of the hydrogen content x and the chemical states, as well as XRD results of the Nb hydrides.

The energy and angular distributions of particles scattered Ar⁺ ions on the surface of InGaP(001)<110> have been calculated. The correlation between experimental and calculated angular distributions of the scattered particles has been presented. It has been shown that the semichanneled ions formed the characteristic peaks in the energy distributions of the scattered particles.

Equations on excitation and light emission of the localized bulk and surface plasmons for metal nanostructures in dielectrics by electron beam are derived using the localized plasmon theory in the random phase approximation at high frequency condition. These are applied to calculate inelastic scattering probabilities of electron beams and light emission intensities by the localized plasmon excitations for metal nanospheres and ultrathin films in dielectrics using the quasi-static and electric dipole approximations. It is also assumed that local dielectric functions for metals and dielectrics have step function shapes at the metal and dielectric interfaces. It is found that the electron beams are inelastically scattered by the localized surface and bulk plasmons with various excitation modes, but the light is emitted only from the localized surface plasmons with specific excitation modes within these approximations.

In this paper, we aim to automatically provide a solution to peak separation in an X-ray photoelectron spectroscopy (XPS) spectrum with non-negligible statistical noise that is inevitably accepted in multi-dimensional (e.g., 2-dimensional/3-dimensional XPS profiles) XPS measurement. To achieve this, in our previous study [H. Shinotsuka et al., J. Electron Spectros. Relat. Phenomena 239, 146903 (2020)], we automatically selected optimal solutions using the Bayesian information criterion (BIC) for measured XPS spectra. This was successfully performed for many varieties of XPS spectra. However, the optimal solution rarely included a small and sharp peak that was likely to be caused by statistical noise. In this study, we investigate a practical method to eliminate the infrequent solution with a noise-derived peak. This method uses hierarchical clustering with peak parameters (i.e., width and area) as a preprocessing step before selecting the solutions using the BIC.

Nickel and nickel-based alloys as protective coatings are used in various applications where the corrosion resistance is required. They have been widely used in automotive, aircraft, marine, nuclear power plant, oil, and gas industries. This work aims at fabricating nickel layers on copper alloy substrates through electroplating techniques with different electrolyte temperatures (20, 30, and 50°C). The effect of the electrolyte temperature on the electroplated nickel layers was investigated by using a field emission scanning electron microscope, an X-ray diffraction (XRD), a potentiostat, a camera, and a microhardness test. It is expected that electrolyte temperatures could influence the surface morphology, crystallographic orientation, the electrochemical behavior, wettability, and the hardness of the nickel layers. The surface morphology shows differences in terms of the roughness and the grain size for various samples. Raising the electrolyte temperature from 20 to 50°C results in the increase of the water contact angles and the decrease in the hardness of the Ni layers, while the crystallite size has a maximum value at 30°C. Moreover, the different XRD intensity from the (111) planes shows a significant influence on the corrosion resistance.

This study focuses on the synthesis of lithium-exchange silica (Si/Li) particles and their corrosion protection for aluminum alloy substrates. Silica is synthesized via a sol-gel method as a raw material to prepare Si/Li in a saturated lithium nitrate solution. The obtained samples are characterized by X-ray diffraction, field emission scanning electron microscopy, zeta potential measurements, Fourier transform infrared spectroscopy, and inductively coupled plasma mass spectroscopy. Inhibition properties of synthesized Si/Li are investigated by electrochemical impedance spectroscopy (EIS). The results show that Si/Li prepared in the saturated lithium nitrate solution has a high content of loaded lithium. This amount relates to a high and stable corrosion protection of Si/Li in the electrolyte solution for the aluminum alloy substrate. After 96 h of immersion in the electrolyte solution, electrochemical results show a high value of an inhibition efficiency up to 98%. Water-based epoxy coatings containing Si/Li are also prepared to highlight their corrosion protection efficiency for the aluminum alloy substrate. Concerning the EIS measurement results, the coating containing 5 wt% Si/Li shows high and stable barrier properties for a long immersion time in the protection of the aluminum alloy substrate.

Extended X-ray absorption fine structure (EXAFS) plays an important role in the surface science and nanotechnology to characterize the non-crystalline materials using the curve fitting (CF) analysis. However, the CF has problems such as correlation between the structural parameters, the dependence on initial parameters, and the limitation of degree of freedom when EXAFS is applied to the complex system. In this paper, we propose a thorough search (TS) method to solve these problems. We analyzed EXAFS data for molybdenum oxide (α-MoO₃) using the TS method. MO₃ possesses a well-defined but complex local structure in which a central molybdenum (Mo) atom is surrounded by six oxygen (O) atoms. In CF analysis, the correlations of these six Mo—O bonds make it very difficult to derive reliable structural parameters from EXAFS data. In the TS analysis, the structural parameters regarded as a point (𝒫) were surveyed thoroughly over a certain range. The goodness of fit was evaluated by R-factor. All 𝒫 with R-factors less than a certain value were accepted. The accepted points 𝒫 made a domain in which it was assumed that all points 𝒫 in the domain should occur with equal probability and consequently their averages were used as representative structural parameters. If multiple independent domains were obtained, they were all regarded as possible candidates and the TS analysis provided possible structural parameters. The feasibility and advantages of the TS method were compared with the CF analysis and the micro reverse Monte Carlo method.

Quantitative analysis of crosslinked structure in vulcanized rubber is not enough. There have been some methods based on mechanical properties but no methods to obtain only information on the crosslinked structure. We have solved that problem by curve fitting of sulfur K-edge near-edge X-ray absorption fine structure (NEXAFS) spectra. NEXAFS is useful to determine the chemical structure of the target element. The crosslinked structure obtained by NEXAFS shows a high correlation with the orthodox method. We have established the useful method to assist the orthodox analysis results. We have clarified the relationship between heat resistance of rubber materials and crosslinked structure using NEXAFS in this study.

Five kinds of activated carbon (AC1, AC2, AC3, AC4, and AC5) were prepared, and the characteristics (scanning electron microscopy images, specific surface area, pore-volume, pH_pzc, surface functional groups, and surface hydroxyl groups) of each activated carbon were investigated. Additionally, the adsorption capability of activated carbons and adsorption mechanisms involved in adsorption of cationic and anionic dyes from the aqueous solution were evaluated. The results suggested that the treatment of activated carbon with silver (AC3), titanium oxide (AC4), or magnetic field (AC5) was not useful for increasing specific surface area and micropore volume. Moreover, the amount of cationic and anionic dyes adsorbed using activated carbon prepared from coconut shells (AC1 and AC2) were higher than that adsorbed using AC3, AC4, and AC5. Subsequently, the adsorption mechanism involved in adsorption of cationic and anionic dyes was also assessed. It was found that the amount of cationic and anionic dyes adsorbed was related to the specific surface area, micropore volume, and acidic or basic functional groups. Finally, the interactions between dyes and AC1 were elucidated in this study. Adsorption of dyes onto the AC1 surface was confirmed by the elemental distribution and X-ray photoelectron spectroscopy analysis. These results provide useful information on the surface interactions between the activated carbon and dyes (high molecular organic compounds).

Electrodeposition of paramagnetic copper (Cu) from a sulfate solution was investigated under magnetic fields and two different current densities. Static magnetic fields have been used during electrodeposition of paramagnetic Cu onto paramagnetic aluminum (Al) substrate to enhance the deposition rate and to alter crystallographic orientation and morphology of the film. The magnetic field might be attributed to the field-induced convection that disrupts the depletion layer near the electrode and that might also be correlated to Cu, Al, and oxygen dissolved in the solution as paramagnetic materials. An X-ray diffractometry, a scanning electron microscope with energy dispersive spectrometry, a potentiostat, and a digital camera were used for characterizing the crystal structure, morphology, the electrochemical behavior, and wettability, respectively. The results show that, at the current density of 10 mA cm⁻², raising the magnetic field from 800 to 1400 G increases the cathode current efficiency and alters the electrochemical behavior, the crystal growth, and the crystallite size. At the current density of 30 mA cm⁻², the magnetic field alters the growth and crystallographic orientation. The static magnetic field exposed during electrodeposition of Cu onto the Al alloy can control the film properties, especially crystallographic orientation and the oxygen content.

The evolution of calcium silicate based cements in the field of dentistry has been rewarding. It offers a plethora of advantages with respect to physicochemical and biological properties. However, the extended setting time and limited antibacterial activity in these cements is quite a concern. This study aimed to develop a fast-setting nanoparticle incorporated root-end filling material for use after periapical surgeries. With the incorporation of the silver nanoparticles, and using calcium chloride as the liquid component, the desirable study outcome was achieved. The setting time was significantly reduced when compared to the commercially available root-end filling material.

The paper describes the impact of the crystallographic orientation of an n-type GaAs substrate on the electrical properties of a sulfonated polyaniline (SPAN) thin film with a thickness of 120 nm grown on different n-type GaAs substrates orientation, which are (100), (311)A, and (311)B GaAs planes. Electrical characterization was performed by using current density-voltage (J−V) at room temperature and different temperatures (60−360 K). An ideality factor (n), a Schottky barrier height (Φ_b), and an activation energy (E_a) were extracted from forward J−V characteristics. From the J−V results, it was obtained that the rectification value at 0.5 V for the SPAN/(311)B GaAs hybrid device is higher than those for SPAN grown on the (100) and (311)A GaAs planes. Furthermore, as the temperature of the three heterojunction devices rises, the value of Φ_b increases, n drops, and E_a rises. The E_a measurements revealed that E_a for the SPAN/(311)B n-type GaAs heterostructure is lower than those for SPAN samples grown on the (100) and (311)A n-type GaAs planes. This could be related to the low number of defects in SPAN/(311)B than the other two samples. These results make SPAN with a thickness of 120 nm grown on the high index GaAs planes an interesting hybrid device for future devices applications.

The corrosion and partial discharge of the aluminum alloy conductor, which may occur during operation, can be reduced by coating the aluminum alloy with other materials. This research investigates the corrosion and partial discharge of the aluminum alloy conductor coated with polyurethane/carbon/organoclay (PCClay) composite materials. Polyurethane as a matrix, and carbon and organoclay as a filler were used as composites. Potentiodynamic and partial charge tests were conducted to measure the corrosion rate and partial discharge behavior versus volt age. The results showed that increasing the filler content may lead to agglomeration, decrease corrosion resistance, and decrease partial discharge. The voltage, where the initial partial discharge occurs, increases as the filler content increases.

We discuss the possibility of using adsorbed CO for adsorbate mediated surface analysis. CO is known to exhibit properties that depend strongly on the local environment, e.g., coordination on surface sites, which manifest through its vibrational frequency. This, in turn, suggests the possibility of probing the surface structure through the changes in C—O stretching frequency during surface diffusion. Using density functional theory calculation, we demonstrate that the vibrational frequency shifts of CO manifests the corrugation of the surface, hence, its structure. To show this, we used Cu(410), a wide stepped surface, as our sample.

Polymer electrolyte fuel cells (PEFCs) are a clean, sustainable device to convert chemical energy to electricity and can provide power for automobiles, trains, and ships. In PEFCs, the oxygen reduction reaction (ORR) occurs at the cathode and is catalyzed at electrocatalysts. The activity of ORR electrocatalysts is known to limit the overall performance of PEFCs because the ORR is more sluggish than the hydrogen oxidation reaction at the anode. In the state-of-the-art PEFC, platinum group metal (PGM)-based ORR electrocatalysts are used. Since PGMs are rare and expensive, highly active and durable non-PGM ORR electrocatalysts are required for widespread applications of PEFCs. In nature, metalloenzymes such as cytochrome c oxidase and multicopper oxidases efficiently catalyze the ORR and utilize multinuclear iron and/or copper complexes as active sites. The structure of these active sites and enzyme reaction mechanisms would give us design concepts of artificial non-PGM electrocatalysts for the ORR, possibly leading us to develop next-generation non-PGM electrocatalysts. Herein, recent research progress on understanding enzymatic ORR reaction mechanisms and developing non-PGM ORR electrocatalysts is reviewed from the viewpoint of bio-inspired approaches.

We developed the ellipsometer unit with a switchable mirror holder that can mount two mirrors and switch them without breaking vacuum. The vacuum unit, combined with a differential pumping rotary flange, rotates smoothly with the help of two roll-stands, keeping the optical path stable during an experiment of ellipsometry. The system allows one to efficiently make the measurement at two different photon energies of soft X-ray. Thus, it is useful, for example, in experiments of the resonant magneto-optical Kerr effect on a multi-element magnetic material with an X-ray free electron laser. Moreover, our set-up provides a simple technical tip to rotate a heavy vacuum unit that is attached to a vacuum chamber from the side.

X-ray photoelectron spectroscopy (XPS), ellipsometry, and cathode luminescence were utilized for characterizing oxide films formed on the surfaces of FeCo-V alloys (Permendur) that contained small amounts of aluminum via annealing under a low partial pressure of oxygen. XPS spectra showed that the oxide films were composed primarily of aluminum oxide, which was a result of preferential oxidation of aluminum on the surfaces of the alloys during annealing. The thicknesses of the oxide films were estimated from XPS depth profiles coupled with the sputtering rate of a SO₂/Si film, and the thicknesses were compared with those of the oxide films measured via non-destructive ellipsometry. The thicknesses obtained from the depth profiles may have been overestimated because of a difference in sputtering rate between silicon oxide and aluminum oxide. As measured via ellipsometry, the thickness of the aluminum oxide thin film, which was less than 100 nm, increases with the aluminum content in the alloys. Wide XPS spectra from the sample surfaces with different roughness suggested that the aluminum oxide thin films were homogenously formed on the smooth surfaces, whereas metallic elements in the alloy substrates were detected on the rough surfaces. Furthermore, the electrical resistivity of the alloys with the smooth surfaces increases significantly with the aluminum content, which may be attributable to the formation of the aluminum oxide thin film. These results indicate that the addition of a small amount of aluminum and surface smoothness are important for controlling formation of the aluminum oxide thin films with high resistivity in FeCo-V alloys by annealing under a low partial pressure of oxygen.

The 12th International Symposium “Atomic Level Characterization for New Materials and Devices (ALC ’19)” under the auspices of the 141st Committee on Microbeam Analysis of the Japan Society for the Promotion of Science (JSPS) was held in Miyako Messe, Kyoto, Japan, gathering 265 participants from 13 countries. ALC ’19 was held in conjunction with the 22nd International Conference on Secondary Ion Mass Spectrometry (SIMS-22). In this symposium, 227 papers in total, including three Tutorials, four Plenaries, and one Keynote, have been presented. Twenty five papers out of them are collected in this special issue.

Peter Varga has passed on October 27, 2018. His pioneering discoveries of chemical resolution at the atomic scale on surface alloys, atomic resolution of ultrathin alkali halides, nucleation of bcc iron in ultrathin films, and the microscopic structure of ultrathin alumina films stimulated worldwide research. In recognition of his outstanding scientific contributions, in December 2017 the Japanese Society for the Promotion of Science (JSPS) awarded him a prize for his distinguished contribution on the clarification of surface phenomena by atomic level investigations and the development of novel functional materials. This contribution highlights the life of Peter Varga as a scientist and as a person. With his elegance, his energy, his wit, and his generosity he was a close friend and role model to many of us, and showed us how to combine scientific curiosity and creativity with the lightness of being.

Professor Charles S. Fadley (nicknamed Chuck), who was a global leader in photoelectron spectroscopy using synchrotron radiation, passed away on 1st August 2019 at the age of 77. He was a well-known founder of photoelectron diffraction, and as a front runner in photoelectron spectroscopy using synchrotron radiation he initiated and promoted several novel approaches; such as, photoelectron holography, hard X-ray photoelectron spectroscopy, soft-X-ray standing wave spectroscopy, and more. He contributed to many scientific activities and served scientific communities including this ALC conference. He was an honorable member of the JSPS 141st Committee and a laureate of JSPS 141st Committee Award. This paper summarizes his life to honor his great achievements in science and contributions to scientific communities.

Two-dimensional angle-resolved photoelectron spectroscopy is a powerful method to study the electronic structure of a crystal surface. The latest version of the angle-resolved photoelectron spectroscopy analyzer was installed at the BL6U of the UVSOR-III Synchrotron. This spectrometer consists of a hemispherical electron analyzer equipped with a mechanical deflector and a mesh electrostatic lens close to the sample to make the size of acceptance cone tunable. A constant-energy photoelectron angular distribution of the valence band dispersion cross section in the large wave number region can be efficiently obtained by applying a negative bias voltage to the sample and using a mechanical deflector. Here, the three-dimensional bulk band and the surface state dispersion mappings of Au(111) surface are presented to show the performance of the current photoelectron spectroscopy experimental station. We revisited the dual observation of bulk and surface electronic structures at this kinetic energy regime.

SiO₂-supported NiP binary catalysts show high activity for the non-oxidative coupling of methane (NOCM) reactions, one of the most difficult but important catalytic reactions. We have studied the SiO₂-supported NiP binary catalysts by extended X-ray absorption fine structure (EXAFS) with different Ni : P ratios. NiP binary catalyst with the composition of Ni : P = 1 : 1 was the most active among the three different compositions. EXAFS showed that the NiP catalyst with Ni : P = 1 : 1 had a Ni₂P structure. The structure was stable after the high temperature (1173 K) NOCM reaction conditions for 12 h. It is interesting that Ni₂P shows high catalytic activities in many other reactions such as hydrodesulfurization, hydrogen evolution reaction, and so on. It may be due to the appropriate electronic and geometrical modification of a Ni active site by P.

A Monte Carlo numerical simulation is performed to clarify the reason why an atomic resolution microscope such as a scanning tunneling microscope (STM) cannot give accurately a ppm (parts per million) concentration of elements quantitatively. A relation between the sampling amount and the accuracy has been found. At least 10⁹ atoms are needed to be sampled in order to discriminate the 49 and 50 ppm elemental concentrations. This Monte Carlo result has also been applied to the elemental analysis methods such as ICPAES (inductively-coupled plasma atomic emission spectrometry) and TXRF (total reflection X-ray fluorescence) to clarify the appropriate amount of sampling amount for required precision of quantitative elemental analysis.

Electronic modification of O-terminated ZnO(000-1) and Zn-terminated ZnO(0001) by ethanethiol (C₂H₅SH) adsorption was investigated by angle-resolved photoelectron spectroscopy (ARPES) and X-ray photoelectron spectroscopy (XPS). Ethanethiol dissociates on both surfaces at room temperature to form C₂H₅S and H. The saturation coverage of ethanethiol is nearly three times larger on ZnO(0001) than on ZnO(000-1). This suggests that Zn atoms exposed to the surface should act as adsorption and dissociation sites. Adsorption on the (000-1) surface induces large downward band bending and accompanies a Zn 4s-derived metallic state at the center of the surface Brillouin zone. This proves that ethanethiol is a good electron donor on ZnO(000-1). Contrastingly, ethanethiol on ZnO(0001) hardly affects the energetic position of the ZnO band so that surface metallization is not brought about.

Photoelectron spectroscopy is our main tool to explore the electronic structure of novel material systems, the properties of which are often determined by an intricate interplay of competing interactions. Elucidating the role of this interactions requires studies over an extensive range of energy, momentum, length, and time scales. We show that immersion lens-based momentum microscopy with spin-resolution is able to combine these seemingly divergent requirements in a unifying experimental approach. We will discuss applications to different areas in information research, for example, resistive switching and spintronics. The analysis of resistive switching phenomena in oxides requires high lateral resolution and chemical selectivity, as the processes involve local redox processes and oxygen vacancy migration. In spintronics topological phenomena are currently a hot topic, which lead to complex band structures and spin textures in reciprocal space. Spin-resolved momentum microscopy is uniquely suited to address these aspects.

We have realized a simple and compact new two-dimensional electron analyzer “a VD-WAAEL analyzer” using a variable-deceleration-ratio wide-acceptance-angle electrostatic lens (VD-WAAEL). Using an electron gun and an angle measurement tool, we confirmed that a two-dimensional angular distribution could be measured at once over a large solid angle of ±45°. We also confirmed that energy analysis could be performed with an aperture. Here a high energy resolution of ∼0.23% was obtained by using the aperture size of 0.8 mmø at the 40° position. Moreover, a magnified image of SUS316 #100 mesh was successfully measured. The magnification ratio was 25, which was in good agreement with the calculation.

To elucidate bottom-up fabrication of heterostructures of two-dimensional materials such as graphene and h-BN, C atom adsorption on Cu(111) surface partially covered with h-BN or graphene is studied by using the first-principles method with van der Waals correction. It is found that the C monomer more difficultly locates under h-BN than under graphene or on bare Cu, while the C monomer also more hardly diffuses under graphene than under h-BN or on bare Cu. In addition, formation of C dimers is more difficult under graphene than under h-BN or on bare Cu. These results suggest that we can control the heterostructure growth by modulating growth condition. It is further found that the shape of h-BN or graphene flake on the Cu surface depends on whether the edge is terminated with hydrogen (H) or not. Because the bond formation energy of edges with H atoms are different between h-BN and graphene, it is indicated that appropriate choice of H condition will lead us to the intentional formation of lateral and vertical heterostructures.

The zeta (ζ) factor proposed by Watanabe and Williams [M. Watanabe and D. B. Williams, J. Microsc. 221, 89 (2006)] is a fundamental parameter for quantitative X-ray analysis with consideration of X-ray absorption using scanning transmission electron microscopy in combination with silicon drift detectors (STEM-SDD). In this study, the ζ-factors for Fe and Mn in iron-based alloy systems were determined by two thin-film approaches, namely, the “lift-off method” and the “direct deposition method”. The Mn content in the Fe-Mn alloy obtained by using the ζ-factor, which was measured with Mn thin films directly deposited on a transmission electron microscopy (TEM) mesh grid, was in good agreement with the composition determined by fluorescent X-ray analysis. Determination of the accurate film thicknesses is essential for the accurate measurement of the ζ-factors. A layered structure and a directly deposited thin film is found effective for a standard sample to prevent bending and overlapping of samples. It is proved that the proposed method to fabricate the standard sample is useful for quantitative X-ray analysis with existing STEM-SDD system.

Selection of the cluster size of an ion beam is a key factor for controlling sputtering speeds or the damaged layer of polymer materials. We developed a two rotating electric fields (REFs) type of mass spectrum (MS) filter or analyzer using a novel principle. The REF-MS can continuously separate typical sizes of cluster ions by optimizing the frequencies of the REFs. In this study, we developed an electrospray ionization (ESI) gun column to optimize the cluster sizes of a water ion beam by REF-MS. Annular ring patterns of size-selected clusters were observed using optimized focusing frequencies on typical water molecule clusters. The patterns were compared with the results of the finite difference simulation method. We sputtered a spin-coated polymer film using a size-filtered water cluster ion beam. A sputtering crater was observed on the polystyrene film sputtered by the size-optimized water cluster ion beam. Here, we discuss the cluster size dependence of sputtering speeds for an ion beam for typical numbers of water clusters.

It is known that insulating films charge up positively or negatively under electron beam irradiation. The potential distribution produced at the specimen surface can be measured by our homemade electrostatic force microscope installed in a scanning electron microscope. A global charging, found within several mm from the irradiation area is made by fogging electrons, which are generated by multiple backscattering events between the specimen and the objective lens plate. Since the most of the energy of fogging electrons is less than 5 eV, the global charging can be suppressed at the specimen by applying −5 V to the specimen. On the other hand, the local charging at the irradiation point shows a positive charging in a small dose, but as the dose increases a negative charging is obtained. By increasing the dose further, a positive charging is found. We found two non-charging conditions of insulating film under electron beam irradiation.

We have prepared La₂O₃ supported Ga₂O₃ (Ga₂O₃/La₂O₃) photocatalyst to improve the photocatalytic activity of Ga₂O₃ for CO₂ reduction with water under ultraviolet light irradiation without a noble metal cocatalyst. Significant improvement on both CO₂ reduction and water splitting was attained compared with those for non-supported Ga₂O₃ and La₂O₃. The improvement is attributed to the transformation of the La₂O₃ surface to NaLa(CO₃)₂ during the photocatalytic reduction tests in aqueous solution of NaHCO₃. NaLa(CO₃)₂ was preferentially formed on the surface of La₂O₃ without changing Ga₂O₃ resulting in the structure of Ga₂O₃ supported by NaLa(CO₃)₂. Once NaLa(CO₃)₂ fully covered the surface of La₂O₃, the high catalytic activity was kept long.

The concept of three-dimensional (3D) shave-off secondary ion mass spectrometry (SIMS) is that enables to obtain the depth information of the sample simultaneously with the mass information using the vertical axis of a two-dimensional position-sensitive detector in the mass analyzer. In this study, we simulated the trajectory of secondary ions sputtered from a virtual sample in the 3D shave-off SIMS system and investigated the magnification ratio of the ions. The simulation results showed that we could distinguish the depth position of the secondary ions sputtered from a sample by the detected position in our concept of 3D shave-off SIMS.

We present two quantum trajectory approaches for the simulation of electron backscatter diffraction (EBSD). The quantum trajectory approaches are based on Schrödinger equation and they yield excellent agreements with experimental patterns. Meanwhile, they are particle models that allow ones to intuitively understand the processes of electron diffraction in a classical way. Besides, the approaches have significant advantages in computation efficiency. Because of the accuracy, intuitiveness, and efficiency, the trajectory approaches allow us a deeper understanding of the physical processes of EBSD.

Optical properties of several transition metals, namely 3d (Fe, Ni, Co, Cu), 4d (Ru, Rh, Pd, Ag), and 5d (Os, Ir, Pt, Au) metals, for the application of surface plasmon resonance (SPR) were investigated. Using first-principles density functional theory method, we calculated the optical conductivities and the dielectric constant by including contributions from intraband and interband transitions. The calculated results for all systems reproduce the experimental trends qualitatively. The contribution of the Drude model is very dominant at low energy levels and gives a tail effect to the spectrum. Peaks in optical conductivity can be observed, which can be related to interband transitions. The SPR reflectance curve based on the Kretschmann configuration has further been simulated.

The Auger electron intensities of Si-LVV and Ag-MNN from a Si(111)7×7 and a Si(111)√3×√3-Ag surfaces were measured for varying glancing angles of the incident electron beam in reflection high-energy electron diffraction, known as the beam rocking Auger electron spectroscopy (BRAES). The energy of incident electron beams used was 10 and 5 keV. The intensity anomalies observed in these BRAES profiles on the surface wave resonance condition were more pronounced for the 5-keV incident beam than for the 10-keV beam. It was found from BRAES profiles of the Si(111)√3×√3-Ag surface by the 5-keV incident beam that the intensity enhancements of Si-LVV differed from those of Ag-MNN at the [112] incidence, but were similar at the [101] incidence. This result can be interpreted qualitatively by the wave field periodicity parallel to the surface.

Dynamic behaviors of atoms on a material surface are important processes for catalytic reactions and crystal growth. Visualizing their processes will contribute to understanding reaction mechanisms and the process of surface structural formation. Scanning tunneling microscopy (STM) is a powerful tool to investigate the surface structure of solid materials and has been used to observe the atomic structures of various important materials such as metals and semiconductors. However, the scan speed of conventional scanning tunneling microscopes is too slow to capture dynamic processes of surface atoms in real time. In this study, we developed a new scanner for high-speed STM (HS-STM). This scanner is constructed from a flexure structure actuating in the x and y directions and a small piezoactuator actuating an STM tip in the z direction. To enhance the actuation bandwidth, the tip holder was minimized and the flexure was hardened. We successfully imaged atomic structures on both highly oriented pyrolytic graphite under ambient conditions and a Si(111) under ultrahigh vacuum at 1 frame s⁻¹ using the developed HS-STM scanner.

Long linear carbon chains (LCCs) encapsulated in carbon nanotubes (CNTs) were produced on a film scale by field emission discharge of CNT films. LCCs inside CNTs were characterized by Raman spectroscopy and transmission electron microscopy. After an electric discharge of a CNT film cathode, long LCCs encapsulated in single-wall CNTs as well as double-wall and triple-wall CNTs were formed in the film. The length of LCCs is longer than 30 nm (i.e., more than 230 carbon atoms). Not only a single LCC but also two or three LCCs in parallel inside a CNT were found. Raman spectra showed prominent peaks, called “LCC bands”, in a region from 1790 to 1860 cm⁻¹ originating from longitudinal optical phonons of LCCs. The observation of strong LCC bands are due to resonance Raman scattering, i.e., the excitation photon energies between 1.85—2.54 eV match with energy gaps of the long LCCs inside CNTs.

It is well known that Ag loaded Gallium oxide (Ag/Ga₂O₃) promotes photocatalytic CO₂ reduction to CO. However, the role of the Ag co-catalyst in the CO₂ reduction has not been clarified. We have intended to find the relationship between the state of Ag loaded on Ga₂O₃ and their activity for the photocatalytic CO₂ reduction. To achieve this, we have tried to control and stabilize the loading state of Ag on Ga₂O₃ during their use for the photocatalytic CO₂ reduction by adding methanol as a reducing agent. It is confirmed that methanol stabilizes the particle sizes of Ag nanoparticles (Ag-NPs) loaded on Ga₂O₃ under the photocatalytic CO₂ reduction condition and is hardly decomposed to produce CO. Using Ga₂O₃ loaded with size-controlled Ag-NPs as a photocatalyst for the CO₂ reduction, it is found that Ag-NPs with their sizes within 10—30 nm are active sites for the photocatalytic CO₂ reduction and the catalytic activity linearly increases with the increase of the number density of Ag-NPs. However, a higher Ag loading amount over 1.0 wt% promotes aggregation of Ag to be larger metal particles over 70 nm which are not active for the CO₂ reduction.

Contribution of main chains and side chains of unrubbed polyimide films with steroidal structure side chains to second harmonic generation (SHG) response was studied by varying their molar fraction of side-chain diamine. The SHG intensity in P_in/P_out polarization (P-polarization input and P-polarization output) configuration does not depend strongly on the molar fraction. This indicates that both the main chains and side chains at the surface contribute similarly to the SHG intensity. The SHG intensity in S_in/P_out polarization configuration normalized by that of P_in/P_out polarization configuration was the smallest for the molar fraction of side-chain diamine of 0%. This fact indicates that the microscopic nonlinear dipoles are standing nearly upright at the surface of the film consisting only of the main chains, while their orientational spread is wider when the side chains are involved.

We used sum frequency generation (SFG) spectroscopy to study the desorption of hydrogen on the stepped Si(111) surface with a miscut angle of 9.5° toward the [112] direction in ultra-high vacuum. The terrace peak was observed at 2085 cm⁻¹ and the vertical step mode of dihydride was observed at 2098 cm⁻¹ for the ssp-polarization (s-polarized SFG, s-polarized visible, and p-polarized infrared light) combination. The intensity reduction of these two peaks was monitored directly as a function of time at sample temperatures of 593 K. The rate of reduction was faster for the step dihydride peak than for the terrace monohydride peak.

Atomic scale tungsten (W) pyramids coated with monolayer films of noble metals can be produced on the apex of a W tip sharpened by means of chemical etching. In this work, we produced Pd- and Au-coated nanopyramids using W tips with different apex curvature radii as a substrate and examined the yield ratios of the nanopyramid formation. When the curvature radius is larger than 15 nm, both Pd- and Au-coated W nanopyramids grow. However, when the radius is less than 15 nm, only Au-coated nanopyramids grow. We propose that the preferential growth for the Au case is associated with previous calculation results demonstrating that the difference in the anisotropy of the surface energy between the Au/W(111) and Au/W(211) systems is substantial [S. P. Chen, Surf. Sci. 274, L619 (1992)].

The synthetic polymer, poly(ethylene glycol) (PEG), was mass analyzed by using atom probe (AP). The AP mass spectrum of PEG showed no molecular ions but simple fragment ions of single charge. The sequential correlation between ions is also examined to make clear the requirement for future analyses.

In the Internet of Things (IoT) era using Big Data, metrology is recognized as a crucial process that provides added value in hyper-scaling semiconductor manufacturing processes. Miniaturization of semiconductors requires the discussion of quantum theory on the order of tens of nanometers, and metrology (measurement technology) that supports this requirement has the potential of creating new research fields. Super-resolution optical technology is a common measurement technique that exceeds the physical limit. Moreover, advanced integrated metrology techniques, which include a combination of various kinds of metrology techniques coupled with artificial intelligence (AI) and machine learning (ML), have the potential to evolve into an untapped technological field required by the market. We conduct extensive discussions on the implications of AI/ML. A new way of advanced integrated metrology can be considered as an important role for the fabrication of next generation integrated circuit and be connected to value-added creation.