A5041227267- Graphene research and applications
- Boron and Carbon Nanomaterials Research
- Carbon Nanotubes in Composites
- Surface and Thin Film Phenomena
- Molecular Junctions and Nanostructures
- Semiconductor materials and devices
- 2D Materials and Applications
- Quantum and electron transport phenomena
- Semiconductor materials and interfaces
- Fullerene Chemistry and Applications
- Enzyme Catalysis and Immobilization
- Analytical Chemistry and Chromatography
- Force Microscopy Techniques and Applications
- Gas Sensing Nanomaterials and Sensors
- MXene and MAX Phase Materials
- Semiconductor Quantum Structures and Devices
- Nanowire Synthesis and Applications
- Advancements in Battery Materials
- Supercapacitor Materials and Fabrication
- Nanopore and Nanochannel Transport Studies
- Silicon Nanostructures and Photoluminescence
- Advancements in Semiconductor Devices and Circuit Design
- Hydrogen Storage and Materials
- Thermal properties of materials
- Thin-Film Transistor Technologies
Kyushu University
2022-2024
Tokyo Institute of Technology
2013-2022
Institute of Natural Science
2015
The University of Tokyo
2005-2015
Japan Science and Technology Agency
2008-2011
Tokyo University of Science
2005
National Institute for Materials Science
2005
Osaka University
2001-2004
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTQuantitative analyses of biochemical kinetic resolutions enantiomersChing Shih Chen, Y. Fujimoto, Gary Girdaukas, and Charles J. SihCite this: Am. Chem. Soc. 1982, 104, 25, 7294–7299Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Published inissue 1 December 1982https://pubs.acs.org/doi/10.1021/ja00389a064https://doi.org/10.1021/ja00389a064research-articleACS PublicationsRequest reuse permissionsArticle...
We investigate nitrogen-doping effects in a graphene sheet using first-principles electronic-structure study the framework of density-functional theory. As possible configurations nitrogen impurities graphene, substitutional and pyridine-type defects around monovacancy divacancy are considered, their energetics electronic structures discussed. The formation-energy calculations suggest that doping atom into is energetically most favorable among configurations. Furthermore, by comparison total...
We present an efficient and highly accurate calculation method to provide first-principles electronic structures, current flow under steady states, electric conductance for a nanoscale junction attached truly semi-infinite crystalline electrodes on both sides. This is formulated by the real-space finite-difference approach within framework of density functional theory. In our formalism, scattering wave function infinitely extending over entire system can be determined carrying out...
We investigate hydrogen adsorption effects on stabilities and electronic properties of nitrogen defects in graphene using first-principles electronic-structure calculations within the density-functional theory. find that atoms pyridine-type becomes energetically favorable, whereas case substitutional defect unfavorable. also a transition from p-type to n-type doping occurs by defects, suggesting even carrier type is controllable nitrogen-doped graphene.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Lipid-Coated Lipase as an Enantioselective Ester Synthesis Catalyst in Homogeneous Organic SolventsYoshio Okahata, Yoshitaka Fujimoto, and Kuniharu IjiroCite this: J. Org. Chem. 1995, 60, 7, 2244–2250Publication Date (Print):April 1, 1995Publication History Published online1 May 2002Published inissue 1 April 1995https://pubs.acs.org/doi/10.1021/jo00112a052https://doi.org/10.1021/jo00112a052research-articleACS PublicationsRequest reuse...
We present first-principles density functional calculations that clarify the electronic properties of carbon defects in hexagonal boron nitride $(h$-BN) monolayers under biaxially applied strains. find strain can control ionization energies both donor and acceptor states. Furthermore, we also lead to dramatic change conduction channel states due interchange conduction-band-minimum state with nearly-free-electron state. report simulated scanning tunneling microscopy (STM) images $h$-BN for...
We perform first-principles total-energy calculations to investigate stabilities and electronic properties of hexagonal boron nitride ($h$-BN) bilayers under biaxial tensile strains. The possible stacking patterns $h$-BN are investigated in detail. show that the interlayer distances between two layers can be changed applied strains, furthermore, they decrease increase depending on bilayers. find band gaps tunable by applying also strains give rise a transformation from an indirect-...
An adequate interpretation of scanning tunneling microscopy (STM) images the clean Si(001) surface is presented. We have performed both STM observations and ab initio simulations for buckled dimers at ${S}_{A}$ step surface. By comparing experimental results with theoretical ones, it revealed that depend on sample bias tip-sample separation. This enables us to elucidate relationship between corrugation in atomic structure dimers. Moreover, these changes, we analyze details spatial...
First-principles electronic-structure calculations have been performed to examine electronic properties of hexagonal boron nitride (h-BN) monolayers. The dispersion the energy bands and width band gaps are calculated under biaxial strains. It is found that gap decreases as tensile strain increases, whereas increases then it compressive increases. relationship between energy-band structures applied strains reported clarify unique behaviors induced by
Abstract Boron-based two-dimensional materials are of interest for use in electronic devices and catalytic applications, which it is important that they chemically stable. Here, we explore the chemical stability hydrogen boride nanosheets water. Experiments reveal mixing water produces negligible amounts hydrogen, suggesting hydrolysis does not occur stable water, contrast to most boron hydride materials. First-principles calculations sheets interact weakly with even presence defects...
We have performed first-principles calculations for body-centered tetragonal (bct) Si and Ge consisting solely of four-fold coordinated elements. The structural optimization has been carried out based on the local density approximation (LDA) in functional theory (DFT). For total-energy minimized structures, quasi-particle spectra calculated using GW approximation. find that bct are new stable crystalline phases reachable under tensile stress with moderate magnitude. also is a semimetal...
Doping with heteroatoms is one of the most effective methods to tailor electronic properties carbon nanomaterials such as graphene and nanotubes, doped heteroatom dopants might therefore provide not only new physical chemical but also novel nanoelectronics/optoelectronics device applications. The boron nitrogen are neighboring elements in periodic table, they considered be good for nanomaterials. We here review recent work doping effects into monolayer well bilayer on basis first-principles...
The adsorption process of hydrogen atom on nitrogen-doped carbon nanotube (CNT) and its effects the electronic properties are investigated using first-principles density-functional methods. As possible sites, three different positions considered to discuss energies N-doped (10,0) CNTs. It is found that favorable site CNT not top nitrogen but atoms next atom. Interestingly, it impurity state induced by doping with shifted from conduction-band minimum valence-band maximum
We report on relationships between interlayer distances and electronic structures of hexagonal boron-nitride (h-BN) bilayers based first-principles density-functional calculations. The energy-band the band-gap values are calculated under uniaxial compressive strains along direction perpendicular to h-BN bilayer sheets. It is found that band gap can be tuned by applying uniaxially. More specifically, value decreases with decreasing two layers bilayer. behaviors gaps explained in terms structures.
We study atomic and electronic structures of hexagonal boron nitride (h-BN) bilayers on the basis first-principles density-functional calculations. The interlayer distances between two layers in h-BN bilayer band gaps are calculated under biaxial tensile strains. It is found that changed when strains applied. also gap decreases as strain increases. tunable by elongations.
We report on atomic structures and energetics of $90\ifmmode^\circ\else\textdegree\fi{}$ dislocation cores in Ge films Si(001) substrates the basis first-principles total-energy calculations. The core structure consisting a row pairs five- seven-membered rings is proposed found to be stable with increasing overlayers. scanning tunneling microscopy images are calculated show possibility observe structure.
We report the development of an efficient and sophisticated procedure for calculating first-principles electronic structure current flow a nanometre-scale system (e.g. nanowire) sandwiched by two truly semi-infinite bulks. The solution Kohn–Sham equation this is so constructed as to joint generalized Bloch functions inside left right bulks together matching them across interfacial region between formalism described quite simply in real-space finite-difference approach within framework...