In this work Cu₂O and CuO thin films were deposited on glass substrates by dc reactive magnetron sputtering by varying a thickness from 100nm to 250nm. An X-ray diffractometer (XRD) was employed subsequently for the phase characterization of the as-deposited films. The surface morphology of the films was observed by an atomic force microscopy (AFM). The optical measurement was performed to calculate optical band gap (E_g) using a UV-Vis Spectrophotometer in a wavelength range of 300 - 800 nm. The Hall Effect Measurement System was used to decide the electrical properties of the deposited thin films. In this study the electrical and optical properties of the deposited thin films were investigated obviously.

We have found that the photocatalytic methane reforming under water vapor is induced at room temperature on surfaces of metal-loaded Ga₂O₃ particulate photocatalysts. In this reaction, we also found that the reaction activity significantly depends on the pressure of methane and the amount of metal co-catalyst. However, detailed reaction mechanisms including the dynamics of photogenerated carriers and surface adsorbed species relevant to the redox reactions of methane have been unclear. To clarify the behavior of photo-excited carriers and the reaction intermediates on the surfaces of Ga₂O₃ photocatalysts, we conducted operand FT-IR spectroscopy under intensity modulation of UV light. Then, we succeeded in observing a clear correlation between the reaction activity and a broad mid-infrared band (1000-5000 cm^-1) derived from the photo-generated electrons.

In this paper the characteristics of solid state dye-sensitized solar cells prepared by reactive magnetron sputtering is described. The solar cells were constructedas basing the Cu₂O/TiO₂ thin film. From the previous research, it was confirmed that the oxygen flow rate during Cu₂O preparation remarkable affects photovoltaic power. In addtion, the optimum value of the oxygen flow rate was 8.5 sccm. In this study, we examined the improvement of photovoltaic power by the change of film structure.

We have reported a high power pulsed magnetron sputtering (HPPMS) system which equipped the third electrode to control the plasma potential positively. It enabled the acceleration of the generated ions within the plasma the to grounded substrate, by which the metal films with a flat surface and dense structure could be obtained. However, the third electrode had to accept the large current, and the cooling of it was considered to be favorable for the stable operation. In this study, we developed the dual cathode HPPMS apparatus. We applied the pulse powers to these cathodes with half-cycle differences, and the cathode voltage during the rest of the period was kept positive. By this, we expect the positive plasma potential throughout the period and the proper cooling of both electrodes (cathodes). In the presentation, the fundamental discharge properties will be reported.

Tokyo Institute of Technology and Toshiba Energy Systems have collaborated on a compact injector for heavy ion cancer therapy. We will present the results of the vacuum test of an o-ring and a metal seal ring with an experimental cavity for improving vacuum performance.

Non-Evaporable Getter (NEG) coating was originally developed at CERN to elevate vacuum properties of particle accelerator beam chambers. In order to meet increasing demands for the NEG coating to be applied in various vacuum systems where further reduction in vacuum pressure is required to improve their performance, we have started a study for the development of a compact magnetron-sputtering source that can deposit the NEG thin film on common vacuum chambers. The design of the coating device and deposition results including surface analyses will be reported.

Polytetrafluoroethylene (PTFE) has various excellent properties and is expected to be applied in a wide range field. In the previous study improvement of PTFE was performed be by ways of various surface modifications. Furthermore, in order to provide other functions while making use of those properties, it has been attempted to modify PTFE in various ways. As well known, it is intended to improve the water repellency and the hydrophilicity by modifying the surface of PTFE by a physical method. In this study, we modified the surface of PTFE by plasma treatment, and investigated the relationship between treatment conditions and metal thin film adhesion.

In recent years, various properties of TiO₂ have attracted attention and the studies have been conducted in a wide field. In the previous study, it attempted to expand the absorption wavelength by inserting Cu₂O in the lower layer and to further improve the photocatalytic effect inserting oxide layer as a diffusion barrier layer in the intermediate layer. In this reserch, it attempt Investigate the optimum formation conditions by inserting ZnO the middle layer and examination of mechanism. Also, it conducted comparative study with previous research.

To elucidate tribological phenomena in nano-confined condition is crucial important subject in nanofabrication processes and MEMS/NEMS. We previously investigated the behaviors of polymer materials (poly(methyl methacrylate) (PMMA) and polyethylene (PE)) under shear flow, and reported that the shear stress and the slipping modes can be changed by the experimental conditions. In this study, shear characteristics of PMMA and PE under shear flow are investigated based on molecular dynamics (MD) simulation.

A large amount of research had been directed at graphene and other two-dimensional (2D) materials due to their vast variety of unique physical properties. Transmission electron microscopes (TEM) are often used to observe the structures of 2D materials. In the observations, radiation damages are occurred by knock-on collision or excitations of the electronic system of the target. Recently, it is reported that graphene is used as coating materials to protect 2D materials from radiation damages. However, which heterostructure configurations are the best for protecting 2D material are not clear yet. In this study, molecular dynamics study including electron irradiation effects were carried out to investigate the shielding effect of graphene for protecting 2D materials.

Synthesis of nanostructures with atomic precision is getting crucial important in nanoscience and technology. Electron-beam induced methods are expected as candidate technologies to control their syntheses, and it becomes possible to observe and fabricate nanostructures in situ manners. One of the methods is to use electron irradiations for promoting the formation of crystalline Si nanodots embedded within an amorphous SiO₂ film. However, there are few technologies to observe the inside of synthesized nanostructures. In this study, molecular dynamics study including electron irradiation effects were carried out to investigate the internal structural changes of amorphous SiO₂ by electron irradiation.

Influence of radiation on electron emission properties of field emitter arrays was investigated. No significant difference could be seen for the 100-tip field emitter array. However, it was found that step noises were more frequently observed for the 1-tip field emitter array as compared to the case without radiation. It was suggested that motion of the atoms on the emitter surface may be more frequent under radiation.

Local structure of 11-Bromo-1-undecanethiol (BUDT) in organic self-assembled monolayer (SAM) chemisorbed on solvents / silver substrate interfaces (Ag/BUDT) were evaluated by using surface-enhanced Raman spectroscopy (SERS). The structure of the C-S moiety of the Ag/BUDT SAM was dependent on the polarity of the solvents. More BUDT formed the trans conformer in the C-S moiety in more polar solvents. On the other hand, in less polar solvents, the number of the trans conformer was decreased, therefore the composition of the SAM become more homegeneous.

Oxygen that is the reactant of oxygen reduction reaction (ORR) is paramagnetic in the ground state, and the ORR activity is improved by applying the external magnetic field to the electrode catalyst. However, the relationship between the spontaneous magnetization of the electrode surface and the ORR is still unclear. In this study, we investigated the perpendicular magnetic anisotropy and ORR characteristics of molecular beam epitaxy Co/Pt(111) ferromagnetic surfaces in order to clarify the influence of the interaction between the magnetic anisotropy and the ORR characteristics.

Titanium is widely used as a biomaterial. The surface is passivated by the surface oxide layer. It is considered that the relationship of bioaffinity between the material surface and bio-tissue is influenced by the surface properties of the titanium oxide layer. Therefore, it is necessary to control the surface properties on the titanium surface. In this study, reactive sputtering with oxygen gas was performed using a titanium metal target. The stoichiometry of titanium oxide film was controlled by changing the flow rate of oxygen gas. The argon gas pressure was also changed. After the sputtering deposition, the films were annealed to control the crystal structures. The chemical components and crystal structures of the films were evaluated by X-ray photoelectron spectroscopy and X-ray diffraction, respectively.

The GaInN films have typically been grown on GaN templates. Crystal defects are generated due to lattice mismatch between GaInN and GaN, though high-quality crystal of GaInN is necessary to devices. In this study, GaInN films were grown on GaN templates at different growth temperatures by RF-MBE. The films were investigated by the XRD-RSM measurements.

Pyridinic nitrogen species were found to create active sites on nitrogen doped carbon catalyst for oxygen reduction reaction (ORR). However, factors to promote the ORR remained to be elucidated. In this work, we focus on ORR mechanisms on flavin enzyme which has pyridinic nitrogen species and is highly active for the ORR within an organism. pH effect on catalytic activity and selectivity of flavin enzyme was investigated by electrochemical methods. The results showed that hydrogen peroxide formation was increased in acidic medium. The mechanisms will also be discussed based on spectroscopic studies.

This study reports the effect of ZnO buffer layer of Al-doped ZnO (AZO) thin films. As a type of buffer layer, We used ZnO thin films and ZnO nano rod which can be deposited in this laboratory.

The clamped-type vacuum couplings are widely used to connect the vacuum equipment and components. This coupling is standardized by ISO 2861:2013 (JIS B 8365) within the nominal bore of 50. The couplings more than the nominal bore of 50, however, are widely used in the world, especially in east Asia. According to the present situation, the standardization of couplings more than 50 was discussed and approved as a PWI in ISO/TC 112/WG 3. In this report, the present status of the couplings more than 50 are investigated mainly with the manufacturers’ catalogues.

New transistors that control the tunneling current between nanogap electrodes by the gateelectric field are intensely investigated. We propose a fabrication method to form a structurein which each of the three terminal electrodes approaches at the nanoscale. The nanogap structures of about 1 nm were formed in a self-assembly by applying a bias voltage during vacuum deposition and confirmed the tunnel current between the three terminal electrodes.

We have investigated the effect of adhesion force on the nanoscale friction using a nanostripe surface structure composed of gold (Au) and iron (Fe). In addition, the result of nanostripe was compared with that of Au and Fe surface. The nanostripe surface showed the characteristic frictional property, which differed from that of Au and Fe. This might be caused by the composition of the nanostripe surface, which composed both of Au and Fe.

It has been reported that the film structure of organic molecules has a great influence on the efficiency of organic semiconductor devices. In this presentation, we focused on the the effect of difference in thiophene ring and benzene ring structure, especially the presence or absence of sulfur atoms on the film structure. We report the results of orientation evaluation using near edge X-ray absorption fine structure(NEXAFS) of α-sexithiophene with thiophene ring deposited and p-sexiphenyl with benzene ring on Au and SiO₂.

Bismuth (Bi) droplets were prepared by thermal dewetting from an epitaxially grown Bi film on silicon (Si). After exposing the Bi droplets to a high-power laser beam (785 nm), a strong enhancement of the Raman signal from the Si substrate beneath nano/microdroplets of Bi was observed. Spatially resolved Raman microscopy indicated that the as-fabricated Bi droplets inhibit the Raman signal from the underlying Si substrate. The Raman intensity of the enhanced Si optical phonons at the Bi droplets became more intense than that of the bare Si substrate. Alterations in Bi optical phonon modes confirmed a loss of long-range ordered crystallinity in the laser exposed droplets. This type of laser-induced lattice disordering in Bi droplets triggers an optical phase change, as its electronic band is easily distorted by structural changes, switching the Raman scattering properties from surface-inhibited to surfaceenhanced Raman scattering.

Van der Waals hetero-structures composed of layered semiconductors such as MoS₂ and other semiconductor materials have been focused recently. In this presentation, I will discuss the optical properties of interlayer excitons, the bound state of electrons and holes separated into each layer, in MoS₂/MoSe₂ hetero-structures. I will also demonstrate the photoluminescence properties of MoS₂/GaN hetero-structure depending on the polarity of GaN substrate.

Two-dimensional self-assembly of a 2-thienyl-type diarylethene was studied by STM at the liquid/solid interface by analyzing the concentration dependence of surface coverage. It was revealed that the assembling process of this compound was highly cooperative. By using high cooperative system, highly sensitive photochemical control of the assembly was demonstrated.

It has been shown that the MoS thin layers can be used as a Field-effect transistors (FET) with a high on/off current ratio. MoS₂ thin layers were deposited onto n-type Si substrates with a 285 nm-thick SiO₂ layer by the mechanical exfoliation. In this paper, MoS₂ FETs were used to detect the adsorption of small molecules such as Cl₂ and TCNQ. It was found that the FET sensors based on thin MoS₂ films exhibited a high sensitivity to the small molecule.

Two-dimensional materials have large surface area, mechanical flexibility and specific electronic states, and are expected to be candidates for new electronic materials and catalyst materials. We recently found that by exchanging the magnesium cations of MgB₂ with protons, hydrogen boride (HB) sheets composed of a composition ratio of H : B = 1 : 1 is formed. In this talk, the results about formation, characterization and properties of HB sheets will be presented.

In this talk, we report numerical studies on mechanism of nanoscale friction and adhesion at surfaces and interfaces. Model potential suitable for high-speed simulation of the frictionat the graphene/graphene and graphene/fullerene interface was developed. Then we succeeded in direct comparison of the simulated force curve with the observed one by including the effect of the cantilever of atomic force microscopy into the potential. Furthermore the compression and friction characteristics of a thin film of sumanene adsorbed onto a gold substrate surface were investigated using molecular dynamics simulation.

The electronic properties of 2D materials are significantly influenced by the interactions with the other chemical species and applied external fields due to its structure only composed of the "surface" and the suppression of the screening effects. In this talk, I would like to introduce the interactions between 2D materials such as graphene, MoS₂, TaS₂ and other chemical species in the energy scale ranging from that for physisorption to covalent boding, and their field effects in terms of the structure and electronic properties.

The on-surface bottom-up growth of graphene nanoribbons (GNRs) enables us to obtain GNRs with atomically-precise edges, which is a promising material for backward diode or tunneling field-effect transistors (TFET). The edge-functionalization of bottom-up GNRs is one of the essential technology required for realizing well-defined GNR heterojunction. The functional groups at the edges of GNR precursors, though, are often detached during on-surface reaction partially due to protonation of GNR edges during cyclo-dehydrogenation. In this study, we report on the on-surface GNR growth using precursors with methylenedioxy functional groups at the edges. We confirmed that the obtained GNRs have oxygen-containing groups at the edges.

The emissivity of graphene is 2.3% and independent from the wavelength. Here, we grow graphene on a hex-Au(001) reconstructed structure, which has quasi-1D periodic potential with the periodicity of 1.44 nm, in order to change the emissivity of graphene to be dependent on the wavelength. The results of angle resolved photoemission spectroscopy showed the modified band structure of graphene. We also observed the decrease in the emissivity of graphene grown on hex-Au(001) reconstructred structure by means of the microscopic spectroscopy of the thermal radiation intensity.

In this study, we achieved in-situ electrical conductance measurement of suspended GNRs with transmission electron microscope (TEM) observation. We got clearn graphene nanoribbons (GNRs), which width was gradually reduced by electron beam sculpting method. We found that the GNR of 250 nm in width showed metallic behavior, while one of 1.8 nm in width showed semiconducting behavior. The transport gap was estimated to be 0.3 V, which was similar to the previous data.

There are some previous researches which focus on electron-phonon interaction matrix elements of graphene and draw the obtained matrix elements for electrons with some initial state and final state. However, the intensity distributions of matrix elements in unoccupied states at Gamma point, which are related to relaxation of hot carriers, have not been analyzed yet. In this study, we did first-principles calculation of the electron-phonon interaction of graphene, and analyzed the intensity distributions of its matrix elements in occupied states and unoccupied states.

Recent progress of our research on CVD growth of two-dimensional materials, such as graphene, hexagonal boron nitride (h-BN), and transition metal dichalcogenides (TMDCs), as well as their heterostructures will be introduced.

In this study, we have investigated thermoelectric (TE) effects of bilayer graphene (BLG) under vertical electric field using Kubo's linear response theory combined with thermal Green's function technique. As a result, the TE performance of the BLG can be improved by applying vertical electric field. Furthermore, our results within constant-τ approximation reproduce experimental ones, and the averaged grain diameter, estimated under the assumption that the relaxation time τ is determined by the grain boundary scattering in polycrystalline BLG, is in excellent agreement with the typical grain diameter of the polycrystalline BLG sample.

We produced Nafion/graphene/Nafion sandwich membrane, and membrane electrode assembly was fabricated to evaluate permeability of hydrogen ion isotope of the graphene. The currents across the graphene which originate from hydrogen ion isotope were measured, and the permeability was analyzed. We also evaluated the permeability of defect induced graphene

Graphene is used for electrode materials due to its high mechanical strength and electric conductivity. Furthermore, covering arbitrary substrates with chemically modified graphene would give us possibility for developing graphene-based materials. In this study, we modified aryl molecules to graphene CVD-grown on Cu substrate, then we transfer it onto another metal substrate. Surface analysis of the substrate suggest the possibility to transfer chemically modified graphene onto another metal substrate.

To fabricate nanopores in graphene nanoribbon, the transportation of phonons are expected to be blocked, while the electrons can still freely transport with high speed. Such thermoelectric device takes great interest. However, there was almost no report about fabricating nanopores in graphene with fixed shape, controlled size and uniform edge structures. In this presentation, we will introduce our latest progress regarding to nanopores fabrication in graphene by using electron beam of transmission electron microscope.

Two-dimensional (2D) layered materials, such as MoS₂, have recently attracted much attention for both fundamental studies and future technological applications. To use thin 2D layered materials as next generation electric devices and so on, fabrication technology of the ohmic contact between the 2D material and the electrode is indispensable. In this work, we try to fabricate an ideal ohmic contact electrode on 2D molybdenum disulfide (MoS₂) treated with inward-plasma. Depending on the etching conditions, hole-like structures can be formed on the MoS₂ surface. Morphological changes and electrical properties are discussed.

Mass-selected Pt clusters were deposited on the oxide (titania, alumina, ceria) surfaces. The morophology of Pt clusters makes transition from 2D (one layer) → 3D (two layer) → 3D (three layer) depending on the cluster size. The correlation between the morphology and the catalytic activity of CO oxidation reaction by the interaction with the oxide surface was found.

Nonflammable and chemically stable properties of ionic liquids (ILs) are attractive for their application to electric devices such as secondary battery. However, the structuring of ILs faced to some solid materials sometimes cause problems on the efficiency of such devices. To examine how the local structure of the solid electrode affects the structuring of the IL, holes of regulated depth and size are prepared on a graphite surface by heat treatment under Ar flow and position dependent structuring of an IL (BMIM-TFSI) close to the edge of the different depths was analyzed by frequency modulation AFM.

So far, we have developed in-liquid local potential distribution measurement technique based on atomic force microscopy. By using this technique, nanoscale distributions of electrochemical reactions on the catalyst and metal surfaces were visualized. Moreover, we have demonstrated that the measured potential reflects solution potential at solid-liquid interface. In this presentation, we would like to show these results and a newly developed application technique for analyzing charge accumulated at the electrode-electrolyte interfaces.