We have attempted to introduce the ion beam assisted deposition (IBAD) method to prepare LCO thin films at low temperatures and succeeded in crystallizing LCO thin films on Al substrates at a substrate temperature of less than 100 °C. Moreover, charge/discharge tests for LCO films on the aluminum substrates showed voltage plateaus of about 3.6—3.8 V which is typical characteristics of LCO cathodes.

Understanding of time evolution of HiPIHCS discharge physics is important in precise control of growth of nanoparticles. In this study, time resoleved optical emission analysis was perfomed by using Ti hollow cathode discharge in Ar atmopsphere.

Triode high power pulsed sputtering (t-HPPMS) has been attempted to fabricate pointed emitters. By using Hf, which is known to have higher ionization efficiency than Mo, we could fabricate much more sharp HfN emitters with an aspect ratio (AR: half-height/half-width) of up to 2.3. However, shape optimization was necessary to realize the electron emission. In this study, we fabricated a HfN emitter prototype and an emitter with a less protruding tip by reactive t-HPPMS.

Anhydrous LiOH showed NIR absorption bands at 7340 and 7171 cm^–1, which were assigned to the surface OH^– and interlayer OH^– of LiOH, respectively. LiOH·H₂O showed NIR absorption bands at 7137 and 6970 cm^–1, which were assigned to the interlayer OH^– and H₂O coordinated with Li⁺, respectively. Based on the assignments, the hydration behavior of LiOH under ambient conditions was investigated by NIR spectroscopy. Kinetic analysis showed that the hydration of the interlayer OH^– of LiOH proceeded as a second-order reaction, indicating the formation of intermediate species—[Li(H₂O)_x(OH)₄]^3– (x = 1 or 2). However, the hydration of the surface OH^– did not because the coordination of H₂O molecules onto the defect sites of LiOH surface does not require any activation energy.

By using infrared absorption spectroscopy, we observed nuclear spin conversion (NSC) of CH₄ and NH₃ isolated in rare-gas condensed layers. All the experiments were performed in an ultrahigh vacuum. In the measurement of CH₄ trapped in Kr layers, we detected NSC from ortho to meta. By analyzing the integrated intensities of these signals as a function of time, we obtained the NSC rate. In the presentation, we will discuss the NSC mechanism of CH₄ and NH₃.

We experimentally show that the amount of hydrogen absorption does not follow the Sieverts’ law in the hydrogen absorption process using hydrogen absorption material with membrane surface stress sensor (MSS). For this phenomenon, a theoretical model of the hydrogen absorption process via adsorption was constructed using 2-step reaction kinetics. It can be proved that this theory (1) leads to the same result as the Sieverts’ law and the solubility theory, and (2) that the reaction rate of absorption has a Langmuir-type dependency in that the reaction rate of adsorption is much faster than the one of absorption.

The purpose of our study is to develop a spin-polarized atomic hydrogen beam (SPH), and apply it to surface science studies. Molecular hydrogen is dissociated into atoms by 2.45 GHz microwave discharge and the spin of the hydrogen atoms is selected by using a hexapole magnet to obtain SPH. In this presentation, we will discuss the result of the measurement of the spin polarization of SPH by using the Stern-Gerlach magnet and the calculation of the beam trajectory of SPH.

Low energy ion gun was developed toward the evaluation of the H⁺ permeability of graphene. The ion beam with the kinetic energy of 20 eV showed the energy resolution of 0.5 eV after passing through the electrostatic hemispherical monochromater. The separation of H⁺ and H₂⁺ ions was also achieved by the Wien-type filter. The development of the low energy ion gun is expected to reveal the mechanism of the H⁺ permeation of graphene.

Operando spectroscopy of catalysts is important for understanding reaction mechanism of heterogeneous catalysis. In this presentation, our recent AP-XPS studies on activation and hydrogenation of carbon dioxide on copper-based model catalysts will be discussed as well as experimental detalis and future perspective.

In the methanol synthesis by CO₂ hydrogenation on the Cu catalyst, in order to observe the hydrogenation process after formate(HCOO) and unstable intermediates, formate is adsorbed on the Cu(111) model surface and is hydrogenated by the atomic hydrogen at low temperature. Formate reversibly adopted bidentate and monodentate structures, and a chemical species considered to be dioxymethylene and formaldehyde were observed.

In this study, we have developed Pd nanocatalysts modified with group 13 elements (Ga, Al, B), which promote hydrogenation of carbon dioxide to formic acid. According to the HAADF-STEM and XAFS, it is found that Group 13 elements exist on Pd nanoparticle as oxide cluster. We demonstrated that the modification with GaO_X enhanced the catalytic activity based on the surface exposed Pd, which was ten times higher than that of the unmodified Pd catalyst. Kinetic and DFT calculation indicate that ensemble Pd sites with different charge balances, which is caused by the partial modification with GaO_X, can promote not only the hydrogen dissociation but also the adsorption of HCO₃^- species and hydrogenation of HCO₃^- species.

In this study, we synthesized defective Zr-MOF containing missing-linker defects and applied to photocatalytic hydrogen peroxide production. TG-DTA and NMR results showed that defective Zr-MOF had missing-linker sites terminated by acetates. A much higher hydrogen peroxide concentration was produced when defective Zr-MOF was used under light irradiation than when the pristine Zr-MOF was used. It was demonstrated that not only the improvement of photocatalytic reaction rate originated form promoting the linker-to-cluster charge transfer, but also the suppression of hydrogen peroxide decomposition was due to hydrophobization of Zr-MOFs by introducing missing-linker defects with acetate ligands.

The electrocatalytic N₂ORR activity of noble metals such as Pt is widely studied, and polycrystalline Pd gives the smallest overpotential for the N₂ORR. Tin modification is considered as a promoter that can improve the catalytic activity at Pt or Pd surfaces for electrochemical nitrate reduction. However, there is a lack of studies on the effect of tin-coverage of noble metal electrodes on the electrochemical N₂ORR. Herein, in this work, Pd-Pt alloy (111) and (100) single crystalline electrodes are modified with different surface coverages of Sn and then used for the N₂ORR to discuss the impact of Sn-coverage on the N₂ORR activity.

X-ray absorption near-edge structure (XANES) and photoelectron spectroscopy were used to investigate the active and inactive dopant sites in Si-doped GaN. Si-doped GaN formed two dopant states, which were attributed to Si₃N₄ and SiN_x. From the Si K-edge XANES, the Si₃N₄ state did not exhibit electronic states in the GaN bandgap, indicating inactive dopant sites in GaN, whereas the SiN_x state exhibited bandgap states. Thus, the SiN_x state should act as an active dopant site in Si-doped GaN. The simulation of XANES spectra well reproduced the electronic state in the GaN-bandgap when the Ga atom is replaced by the Si atom, suggesting that the active dopant site may be the Si-substituted Ga sites.

Extended X-ray absorption fine structure (EXAFS) plays an important role in the surface science and nanotechnology to characterize the non-crystalline materials. However, the conventional analytical way—curve fitting (CF) analysis—has the problems when EXAFS is applied to the complex system. We propose a thorough search (TS) method to solve these problems. 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. We analyzed Mo K-edge EXAFS data for molybdenum oxide (α-MoO₃) using the TS method. The feasibility and advantages of the TS method were compared with the other methods.

Allmost the all surface analytical methods are microscopic, and except for the elemental analysis by XPS, there are few macroscopic surface analysis methods such are zeta-potential measurement, impedance-analysis of electrodes or temperature-programmed desorption, which are all indirect and available to limited samples. Here, newly developed reversed double-beam photoacoustic spectroscopy enabling the measurement of energy-resolved distribution of electron traps for metal oxides is introduced.

Electric double-layer organic field-effect transistors (EDL-OFETs) have attracted much attention because of their significantly low operation voltage (<1 V) compared to conventional SiO₂-gated OFETs (>10 V). In EDL-OFETs, a high electric field is generated in the EDL that accumulates in the interfacial region between the organic semiconductor and electrolyte, resulting in a low operation voltage. Therefore, the organic semiconductor/electrolyte interface is especially important. In this study, we investigated this interfacial area by using new electrochemical ATR ultraviolet-visible spectroscopy.

Our study's purpose is the development of novel, low cost, and high-performance SEM by using GOS type planar electron emission source for an electron gun. GOS device is based on a MOS type electron emission device using graphene instead of metal for a gate electrode. The GOS device has excellent features such as operation in low vacuum conditions, very small divergence angle of electron beams, and very high electron emission efficiency of over 30 %. Therefore, the GOS device would make the electron optics and vacuum system of SEM very simple. In this study, we installed the GOS device into the conventional SEM without condenser lenses and demonstrated the observation of the SEM image. The obtained image was very stable and without noise and its probe current is 6.5 pA. In addition, we found the optimal structure of the electron optics for the electron beam divergence angle of approximately 0 degree by the simulation of the electron beam trajectory and this structure will make the SEM image higher resolution.

In this study, we use electric-field induced sum-frequency generation (SFG) spectroscopy to probe the channel formation process of OFETs during operation. For a series of experiments, we prepared OFETs fabricated with 2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene (DPh-BTBT) thin films. The gate dielectric layer was composed of a silicon dioxide and a hexamethyldisilazane (HMDS) monolayer. As a result, we succeeded in probing changes in the internal electric field due to charge accumulation while observing SFG peaks of CH stretching modes. Those molecular vibrational modes were derived from methyl groups of HMDS and phenyl groups of DPh-BTBT. We discuss the correlation between each molecular species and the charge accumulation.

In previous STM studies, water molecules adsorb on the ridges of anatase TiO₂(001)-(1 × 4) surface at low-temperature and do not occur the adsorption at room temperature. In this study, we investigated whether or not water molecules adsorb on the anatase TiO₂(001)-(1 × 4) surface at room temperature by atomic force microscopy. Our results reveal that water molecules adsorb dissociatively on the ridge of (1 × 4) reconstructed surface at room temperature.

Adhesion theory explains that friction is caused by shearing real contact area at microscale. On the other hands, the effect of crystal orientation appears as anisotropy of nanoscale friction, which means the breakdown of macroscale adhesion theory at nanoscale. In this study, we define nanoscale contact at twisted graphene interface using Moiré pattern reflecting stacking structure, and we also attempt to understand the effect of the nanoscale contact on nanoscale friction.

We discussed the effect of probe's mass on the bending oscillation or length extension of the force sensor of the frequency-modulated atomic force microscope (FM-AFM). As the mass of the probe increased, the sensor’s frequency and dynamic spring constant were calculated to decrease in both bending oscillation and length extension, respectively. The reduction ratio is larger for length extension, and in the case of a force sensor that uses length extension such as a length-extension resonator (LER), it is necessary to obtain the atomic force using a model that takes into account the mass of the probe.

Studies combined with STM and light have been widely performed. In this study, we developed UHV LT STM with a built-in optical fiber in order to elucidate the effect of light irradiation to organic molecules on noble metals. The effect of light illumination was studied from the results of noise spectra, STM sample observation, and spectroscopy. Laser intensity dependence on the angle of the polarizer was also checked.

We have investigated the particle size distribution of nanobubbles (NBs) the nanoparticle tracking analysis method and found that the particle size is discrete and increases by a factor of √2. We interpreted that this peculiar particle size distribution is caused by the fact that NBs of the same size tend to coalesce with each other, and simulated the particle size distribution incorporating this effect, and found that it can generally reproduce the experiment. The results of recent studies on the interfacial structure of NBs will also be presented.

Phospholipid bilayer is the basic structure of cell membranes. Artificially formed planar bilayer lipid membrane (BLM) has been widely used as a system for the functional analysis of membrane proteins. However, the measurement method has remained unchanged for several decades. Transmembrane voltage is usually used as the input, and the measured transmembrane current is used as the output of the system. In this work, we propose a method to improve the control of the BLM system by applying a voltage parallel to the BLM (lateral voltage) in addition to the traditional transmembrane voltage. The effects of the lateral voltage on the ion-channel-incorporated BLM systems were investigated.

In this study, we have been developing nano-endoscopy based on 3D-AFM technique. We established a tip fabrication process for inserting the tip into the cell with keeping cells alive, and visualized 3D structures inside the cell in real space. By the developed method, we open the possibility for visualizing intracellular nano-meter scale dynamics which cannot be seen with a super-resolution microscopy.

We prepared cytochrome c oxidase (CcO)-modified gold electrodes through self-assembled monolayers (SAM) of mixed alkanethiols and tracked the surface assembly of bilayer lipid membranes (BLM) and the binding of cytochrome c (Cyt c) to the electrode by time-resolved surface-enhanced infrared absorption (SEIRA) spectroscopy. The SEIRA spectra suggest that terminal functional groups of alkylthiols used for the SAM affected the CcO orientation at the surface and binding amounts of Cyt c to the surface-tethered CcO. Electrochemical measurements of CcO-modified electrodes were performed before and after the Cyt c binding in an oxygen atmosphere. Catalytic cathodic currents, which are associated with the oxygen reduction catalyzed by the CcO, were observed and were increased after the binding of Cyt c.

Covalent organic frameworks (COF) are a relatively new organic material group with periodically distributed pores. We developed a new method to prepare COF films from the gas phase by using “alternating deposition”. From High-resolution scanning transmission microscope images, we found a randomly oriented network structure in a high-temperature annealed (HTA) COF film. We also examined that the HTA-COF film had greater permeance of CO₂ than that of N₂ by the factor of 4.6.

The lecture is given on AFM-based nanomechanics, especially it application to polymeric materials.

Alzheimer's disease (AD) is characterized by the aggregation and accumulation of amyloid β (Aβ) on the surface of the brain cells, but the mechanism of is partially unclear. The interstitial fluid supplies and removes Aβ, keeping the brain in a non-equilibrium condition. However, previous studies have examined the equilibrium close space, ignoring the supply and removal of Aβ. Thus, in the present study, we observed the behavior of Aβ aggregation on the lipid membrane under a non-equilibrium open system constructed in our laboratory. In the non-equilibrium open system, the amount of Aβ monomer adsorbed on the membrane was maintained, which promoted Aβ aggregation. We propose the mechanism in which the amount of adsorption and aggregation of Aβ converges the equilibrium steady state under a close system, which it converges to the non-equilibrium steady state under an open system. In conclusion, our study advocates for the importance of experimental verification under non-equilibrium open space because non-equilibrium open space may be involved in the progression of AD.

The oxidation processes of Hf disilicide on Si(111) substrate [HfSi₂/Si(111)] after supersonic O₂ molecular beam (SOMB) irradiation were investigated with synchrotron radiation soft X-ray photoelectron spectroscopies of Hf 4f, Si 2p, and O 1s core-levels. A direct dissociation process of the impinging O₂ will be discussed from the oxidation progression depending on SOMB kinetic energy (KE) increase. In addition, the potential barrier for oxidation of HfSi₂/Si(111) will be also demonstrated from a stepwise growth of the total area of Hf oxide species depending on KE of SOMB.

It has been reported that the generation of fine particles derived from electrode materials was confirmed by the electric current method in liquid. The formation process of these fine particles is thought to involve three reactions: electrolysis of H₂O, ionization of the electrode material, and growth of the particles by re-reduction of the generated ions. In the present study, electrochemical measurements were carried out using a three-electrode cell in order to investigate the details of the formation process of Au microparticles, and the results obtained are discussed.

In recent research, there have been some attempts to use semiconductors to control catalytic reactions. Photocatalysts could accelerate chemical reactions using the recombination of excited electrons and holes, however, available energy is restricted in semiconductor band gap energy. To achieve chemical reactions with much higher activation energy, we propose another type of electronic excitation: hot carriers leading to chemical reactions. This idea has been demonstrated as desorption by hot carriers from a MOS structure in electronic circuits. When a gate voltage V_G is applied to the metal electrode in MOS, hot carriers tunnel or ballistically move from the substrate through the insulating thin oxide layer and injected into the surface metal layer, which would induce dissociation, association, and desorption reactions of adsorbed molecules on the metal surface. We are challenging dissociation and association processes using a Pd thin film on Si-MOS (Pd/SiO₂/Si), like CO + 1/2 O₂ → CO₂↑ reaction by applying gate voltages. We will report the detailed results in this presentation.

The mineral surfaces are considered to be the reaction field for the concentration polymerization of amino acids in the chemical evolution described in the origin of life. Among minerals, pyrite is the most abundant sulfide mineral on Earth, and the strong adsorption between defects on the pyrite surface and amino acids may cause the polymerization of amino acids. However, the details such as the adhesion state of amino acids remain unexplained. In this study, the adhesion state is elucidated by the adhesion forces between a single amino acid and a defect on the pyrite surface.

In recent year, we have reported that the interface between YDC and CeO₂ synthesized by heterogeneous Y doping into CeO₂ become an active site for photocatalytic water splitting. In this study, YDC-CeO₂ interface was fabricated by hybridization of as-prepared YDC nanoparticles and CeO₂ surface, instead of Y doping. Photocatalytic activity of water splitting against Y concentration and amount of interface was investigated.

An increase in surface area is effective way to enhance photocatalytic activity, then it is important to synthesize nanoparticles. In this study, we attempted to synthesize CeO₂ nanoparticles by crystallized glass method. It was found that crystallization temperature plays an important factor to control the morphology and size of CeO₂ nanoparticles. Relationship between photocatalytic acetaldehyde degradation and crystallization temperature is discussed.

Photocatalytic water splitting is an important issue for sustainable production of hydrogen. In order to improve the photocatalytic activity, photoexcited charge separation plays one of the key factors. In our recent study, we found that the interface between CeO₂ and Sm³⁺ doped CeO₂ formed by heterogeneous doping of Sm³⁺ on CeO₂ surface act as separation sites of photoexcited charge. In this study, Sm₂O₃ nanoparticles were dispersed onto CeO₂ prepared by the flux method, and then heterogeneous doping structures were fabricated by heat-treatment and acid-treatment. Relation between the heterogeneous doping structure and photocatalytic activity is investigated.

The purpose of this study is to investigate photocatalytic degradation decomposition on SrTiO₃ nanoparticles synthesized by the crystallized glass method. Particle size of prepared SrTiO₃ was smaller than that of conventional solid phase method. The effect of the structure of SrTiO₃ prepared by the crystallized glass method on the photocatalytic activity was investigated.

The reactivity of redox reactions is greatly affected by the local structure of the electrode surface on a single-atom/single-molecular scale. Although it is strongly required to investigate the redox reactions on a molecular scale, the number of those reports is limited due to the difficulty of performing in situ measurement with high spatial resolution. In this study, redox reaction of a single ferrocene molecule was observed using an electrochemical scanning tunneling microscope (EC-STM), which is a combination of a scanning tunneling microscope (STM) and electrochemistry (EC). Using a tripod-type molecule as a base, we could stably deposit ferrocenes on the Au (111) electrode both in an isolated and dispersed state, which enables us to observe clear changes in the EC-STM images upon the redox reaction.

Field emission characteristics of carbon nanofilament grown on carbon fiber paper by thermal CVD were investigated. Low threshold electric field of 1.15 V/μm was obtained.

Determination of Mn valence in oxide-substances is quite difficult by conventional methods, i.e. X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF) analysis, etc. Even more difficult that should be for slightly Mn-doped system. We propose that secondary ion mass spectrometry (SIMS) is suitable for determining valence of dilute Mn ion in oxides. In this report, we show an approach to determine Mn valence in BaTiO₃:Mn (less than 1 at.%) from a mass spectrum pattern which consists of several MnOx signals, compared with those of the standard samples, LaMn³⁺O₃ and SrMn⁴⁺O₃.

Field ion microscope (FIM) has the capability to observe the atomic arrangement of the surface of a metal tip. Using FIM images continuously taken during field evaporation, the internal structure of the specimen can be observed by three-dimensional reconstruction of the specimen. However, the compression factor is needed for three-dimensional reconstruction. In order to calculate the compression factor, we automatically identified the crystal orientation of tungsten FIM images using machine learning. As a result, the correct crystal orientation was output for 88% of the total data, indicating the effectiveness of this method.

Black phosphorus, a two-dimensional layered material, is attracting attention as a next-generation nanodevice material, and although the possibility of relaxation near the surface of black phosphorus has been reported by DFT calculations, its surface structure seems to be poorly understood. In this study, we analyzed the structure of black phosphorus using photoelectron holography and compared the experimental images with simulations to observe the surface relaxation.

In this study, we focused on the peak of the graphite (002) [G(002)] plane of neutron-irradiated highly oriented pyrolytic graphite (HOPG) using in-situ X-ray diffraction method and analyzed the structural change during the compression and decompression processes at high temperature in order to understand the details of the transformation mechanism of neutron-irradiated HOPG. It was found that the G(002) peak can be represented by two components from RT to about 600°C, and it can be represented by only one component at the higher temperature in the neutron-irradiated sample, whereas it can be represented by only one component in the unirradiated sample.

Due to the recent technological innovation of intense terahertz (THz) pulses, ultrafast control of crystal and molecular structures using THz electric fields has been extensively studied. In this case, the THz pulse must have a large electric field as large as the Coulomb field between lattice points. In order to image such ultrafast dynamics in real space using time-resolved STM, THz pulses, which play the role of excitation light, are required to have a high repetition of MHz or higher. Using a pulsed laser with a center wavelength of 1030 nm, a pulse duration of 300 fs, and an average power of less than 20 W, and a high repetition rate of 4 MHz, we have developed a strong electric field for THz pulses generated by the optical rectification effect of a nonlinear optical crystal BNA.

We have studied the electron-stimulated desorption from surface of alkali-halides by using grazing angle scattering of protons. When the surface of an alkali halide is irradiated by a few keV of electron energy, several types of defects are created inside the crystal. Numerous defects diffuse in the bulk and form a cluster of defects under the surface which stimulates surface atoms to desorb. Desorption that causes a change in the morphology of the surface is categorized into two types. The 1st is formation of a pit with monolayer depth on a flat surface and the 2nd is desorption from the step edges of the pit. In this study, the changes in desorption yields due to these defects are investigated by comparing the measured scattering intensities of fast protons with calculated ones obtained by a proton-scattering-simulation.

In the layered perovskite-type structure of Sr₂IrO₄, two components were observed in the XPS spectrum of O 1s. Different photoelectron holograms were obtained from each peak, suggesting that there is a difference in the structure around the oxygen.We speculate that this is due to the oxygen at the apex of the IrO₆ Octahedron (SrO layer) and the oxygen in the IrO₂ facet (IrO₂ layer). In our presentation, we will report the detailed analysis and results of these studies.

Characteristic X-rays emitted from artificial mica (KMg₃AlSi₃O₁₀F₂) have been measured using synchrotron radiation as an excitation source. When the energy of the incident X-rays was tuned at the K 1s → 3p* resonance, it was found that the intensity of the Si Kα X-rays was enhance, but that of the Al Kα X-rays was constant. From these results, the intensity change is considered to be specific to the atoms that are located next to potassium. This phenomenon is expected to be applied to elucidate the species of the neighboring atoms of the target atom.

Molecular dynamics simulation was performed to investigate the tribological properties of the sumanene self-assembled monolayer by rubbing with an AFM tip, and marked change in the tribological properties due to AFM-tip indentation was revealed. For the small loading force, FFT analysis of the lateral force curve exhibits the sumanene molecular arrangement and the H atomic arrangement of sumanene. When the tip was pushed toward the surface, sumanene tilted along the tip forward scan direction and returned to its original position for the backward scan. When the tip was pushed further, fracture of the film occurs.

The spatial electromagnetic field was measured by using a scanning electron microscope (SEM).