A5021175624- ZnO doping and properties
- Electron and X-Ray Spectroscopy Techniques
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Catalytic Processes in Materials Science
- Metal and Thin Film Mechanics
- Advanced Chemical Physics Studies
- Copper-based nanomaterials and applications
- Astro and Planetary Science
- Advanced Photocatalysis Techniques
- Ga2O3 and related materials
- Machine Learning in Materials Science
- Gas Sensing Nanomaterials and Sensors
- Advanced materials and composites
- Graphene research and applications
- TiO2 Photocatalysis and Solar Cells
- Catalysis and Hydrodesulfurization Studies
- Corrosion Behavior and Inhibition
- Advanced Condensed Matter Physics
- Topological Materials and Phenomena
- Astrophysics and Star Formation Studies
- Magnetic and transport properties of perovskites and related materials
- X-ray Spectroscopy and Fluorescence Analysis
- Surface and Thin Film Phenomena
- Planetary Science and Exploration
High Energy Accelerator Research Organization
2021-2025
The Graduate University for Advanced Studies, SOKENDAI
2019-2025
Institute of Materials Structure Science
2019-2024
Tokyo Institute of Technology
2013-2022
Deleted Institution
2022
Doshisha University
2021
Gifu University
2020
Kanagawa Environmental Research Center
2020
Tokyo University of Science
2019
University of Tsukuba
2019
Photocatalytic activity is determined by the transport property of photoexcited carriers from interior to surface photocatalysts. Because carrier dynamics influenced a space charge layer (SCL) in subsurface region, an understanding effect potential barrier SCL on behavior essential. Here we have investigated relaxation time single-crystal anatase and rutile TiO2 surfaces time-resolved photoelectron spectroscopy found that recombination, taking nanosecond scale at room temperature, strongly...
Sn-based perovskite solar cells (S-PSCs) are a promising candidate to replace toxic Pb-based PSCs. For promoting their industrial application, developing inorganic substitutions of unstable poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is also an important part due its intrinsic stability and low cost. Here, we in situ prepared ambipolar SnOx by simple fast plasma-assistant strategy (P-SnOx). The as-prepared P-SnOx works as hole transport layer directly, yielding 10.89 ±...
Electronic states formed at the interfaces of molecular semiconductor materials in organic optoelectronic devices are essential for their functionality. However, resolving these complex and disordered practical is challenging. In this study, electronic well-defined p–n heterojunctions by epitaxial growth C60 on single-crystals dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) were characterized X-ray photoelectron spectroscopy yield spectroscopy. Our observations revealed formation...
Intermetallic compounds (IMCs) have unique geometric and electronic structure compared with their component pure metals. We already found that PtCu IMC supported on silica gel was more active than Pt/SiO2 for the preferential oxidation (PROX) of CO in excess hydrogen. In this study, we tried to prepare these particles alumina by liquid-phase reductive deposition (LRD) method, characterized them X-ray diffraction (XRD), transmission electron micrograph (TEM), Fourier transform infrared...
Surface metallization of ${\mathrm{SrTiO}}_{3}(001)$ by hydrogen adsorption is experimentally confirmed for the first time photoemission spectroscopy and surface conductivity measurements. The metallic state assigned to a quantized in space-charge layer induced electron doping from atoms. measured two-dimensional (2D) well above 2D Ioffe-Regel limit indicating that system conduction regime. mean free path estimated be several nanometers at room temperature.
Synchrotron-radiation angle-resolved photoelectron spectroscopy has been utilized to study the interaction of atomic H with nonpolar ZnO($10\overline{1}0$) surface and polar ZnO($000\overline{1}$) (0001) surfaces. adsorption leads semiconductor-to-metal transition on ($000\overline{1}$) Metallization is a consequence formation single metallic band within potential well between surface/vacuum interface barrier edge conduction band, which bent downwardly at surface. The electrons confined in...
We report on the present status of a vacuum ultraviolet and soft X-ray undulator beamline, BL-13A, located at Photon Factory. BL-13A is mainly dedicated to study organic thin films adsorbed well-defined surfaces, using angle-resolved photoelectron spectroscopy (ARPES), (XPS), absorption (XAS). The photon-energy resolution (E/ΔE) estimated be about 10000 photon energy 64 eV with an exit-slit width 30 μm. intensity 2.9 × 1012 5.6 108 photons/s for energies 30-1600 100 μm ring current 450 mA....
Angle-resolved photoelectron spectroscopy utilizing synchrotron radiation is used to investigate the surface electronic structures of nonpolar $\text{ZnO}(10\overline{1}0)$ surfaces covered with hydrogen, methanol, and water. Adsorption these species leads semiconductor-to-metal transition by forming single partially filled metallic bands a $\text{Zn}\text{ }4s$ character. The charge densities are in order ${10}^{12}--{10}^{13}\text{ }{\text{cm}}^{\ensuremath{-}2}$. bottom positions...
Time-resolved soft X-ray photoelectron spectroscopy (PES) experiments were performed with time scales from picoseconds to nanoseconds trace relaxation of surface photovoltage on the ZnO(0001) single crystal in real time. The band diagram has been obtained numerically using PES data, showing a depletion layer which extends 1 μm. Temporal evolution effect is well explained by recombination process thermionic model, giving photoexcited carrier lifetime about ps at under flat condition. This...
Altermagnets are a novel platform to realize exotic electromagnetic properties distinct from those of conventional ferromagnets and antiferromagnets. We report results micro-focused angle-resolved photoemission spectroscopy (ARPES) on RuO2, which altermagnetic nature has been under fierce debate. have elucidated the band structure (100), (110) (101) surfaces bulk single crystal. found that, irrespective surface orientation, experimental structures obtained by ARPES commonly show...
In this study, a clear-cut relationship obtained between the d band centre (Cd) of Ni and Ni3M (M = Ge, Nb, Sn, Ta, Ti) intermetallics their activation energy (Ea) in H2–D2 equilibration provided strong experimental proof for d-band theory. The Cd was lowered by formation intermetallics, making Ni–H(D) bonding weaker Ea lower.
The electronic structure of ternary tin oxide with pyrochlore structure, Sn2Nb2O7, which has the contribution Sn 5s orbitals in valence band, is examined by synchrotron-radiation-excited photoelectron spectroscopy and X-ray absorption together ab initio calculations. empirical spectra are qualitatively consistent calculated density states exception a striking discrepancy around band maximum (VBM). calculation suggests presence sharp peak VBM, mainly due to dispersionless bands that derived...
Photocatalytic activity and lifetime of photoexcited carriers on well-defined single-crystalline anatase rutile TiO2 surfaces with different surface orientation have been systematically studied by photoelectron spectroscopy. activity, evaluated reference to the photocatalytic degradation acetic acid, has a positive linear correlation carrier at crystal surface, which was determined following time evolution ultraviolet-induced photovoltage. This indicates that is prime factor for so it can be...
Morphological stability and catalytic activity of Au nanoflowers (NFs) were improved by using γ-Al<sub>2</sub>O<sub>3</sub> support water extraction procedure. Formation rate acetophenone on NFs/γ-Al<sub>2</sub>O<sub>3</sub> was ten-fold higher than that spherical NPs/γ-Al<sub>2</sub>O<sub>3</sub>.
Two-dimensional (2D) metallic states formed on the $\mathrm{ZnO}(10\overline{1}0)$ surface by hydrogen adsorption have been investigated using angle-resolved photoelectron spectroscopy (ARPES). The observed state is characterized a peak-dip-hump structure at just below Fermi level and long tail extending up to 600 meV in binding energy. peak hump positions are separated about 70 meV, value close excitation energy of longitudinal optical (LO) phonons. Spectral functions formulated basis 2D...
The metallic band structure of the hydrogen-adsorbed SrTiO${}_{3}$(001) surface is studied by polarization-dependent photoemission spectroscopy measurements. With dipole-transition selection arguments, we attributed peaks into Ti 3${d}_{xz}$, 3${d}_{yz}$, and 3${d}_{xy}$ bands. These ${t}_{2g}$ bands are partially filled with electrons upon H-induced downward bending at surface. Energy splitting 3$d$ considered to be induced a quantum confinement along normal ($z$) direction. accompanied...
A series of alumina-supported intermetallic compounds, Pt3Co/Al2O3, PtCu/Al2O3, Pt3Sn/Al2O3 and Pd3Pb/Al2O3, being promising materials as catalysts, were prepared by reduction two metal precursors co-impregnated on γ-Al2O3. As a Pt precursor, [Pt(NH3)4]2+ or PtCl62− was used coupled with the second precursors. Two different procedures, gaseous H2 LiBH4 in liquid phase, also employed compared. Using which possesses more negative potential than strongly enhanced formation desired Pt-based...
Pump–probe time-resolved X-ray photoelectron spectroscopy measurements have been carried out to comparatively assess the relaxation process of photoexcited states on pristine and Ar+-sputtered TiO2(110) surfaces a TiO2(011)-2 × 1 surface, which accumulation-type space charge layers are developed. Ultraviolet laser irradiation induces surface photovoltage (SPV) around 0.1 eV. The SPV time is determined be approximately 100 ns doubled sputtered surface. In contrast, much shorter observed 1....
The adsorption state of ammonia (NH3) on the ZnO(101̄0) surface has been investigated using photoelectron spectroscopy (PES) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. core-level valence-band PES measurements reveal that adsorbs molecularly via its N atom no dissociated species are formed at room temperature. orientation adsorbed NH3 is by polarization-dependent K-edge NEXAFS measurements, it found C3v molecular axis inclined in [0001̄] direction with tilt angle...