Taro Hitosugi

Abstract The development and properties of titanium dioxide (TiO 2 )‐based transparent conducting oxides (TCO), which exhibit properties comparable to those of In 2– x Sn x O 3 (ITO), are reviewed in this article. An epitaxial thin film of anatase Ti 0.94 Nb 0.06 O 2 exhibited a resistivity ( ρ ) of 2.3 × 10 −4 Ω cm and internal transmittance of ∼95% in the visible light region. Furthermore, we prepared polycrystalline films with ρ of 6.4 × 10 −4 Ω cm at room temperature on glass substrates by u

We present electrical transport and optical properties of Ta-doped TiO 2 epitaxial thin films with varying Ta concentration grown by the pulsed laser deposition method. The Ti 0.95 Ta 0.05 O 2 film exhibited a resistivity of 2.5×10 -4 Ω cm at room temperature, and an internal transmittance of 95% in the visible light region. These values are comparable to those of a widely used transparent conducting oxide (TCO), indium tin oxide. Furthermore, this new material falls into a new category of TCOs

Nb-doped anatase TiO2 [Ti0.94Nb0.06O2 (TNO)] films with high electrical conductivity and transparency were fabricated on nonalkali glass using pulsed laser deposition and subsequent annealing in a H2 atmosphere. The amorphous films as deposited on unheated substrates were found to crystallize, forming polycrystalline films at around 350°C. The films annealed at 500°C showed resistivity down to 4.6×10−4Ωcm at room temperature and optical transmittance of 60%–80% in the visible region, which are c

We have investigated electronic band structure of a transparent conducting oxide, Nb-doped anatase TiO2 (TNO), by means of first-principles band calculations and photoemission measurements. The band calculations revealed that Nb 4d orbitals are strongly hybridized with Ti 3d ones to form a d-nature conduction band, without impurity states in the in-gap region, resulting in high carrier density exceeding 1021 cm-3 and excellent optical transparency in the visible region. Furthermore, we confirmed

Length-dependent charge redistribution in dangling-bond (DB) linear chains fabricated on a hydrogen-terminated $\mathrm{Si}(100)\ensuremath{-}(2\ifmmode\times\else\texttimes\fi{}1)$ surface is analyzed by using scanning tunneling microscopy and first-principles calculations. The second-layer Si atoms are displaced alternately to form pairs with charge redistribution, which is explained by the Jahn-Teller distortion in an artificial pseudomolecule. In a short even-numbered (DB) structure, an unpa

Nb-doped anatase TiO2 (Ti0.94Nb0.06O2) films with excellent conductivity and transparency were deposited on non-alkali glass by pulsed laser deposition. X-ray diffraction analysis and transmission electron microscopy confirmed that the obtained films were polycrystalline with anatase structure. The films deposited at a substrate temperature of 250 °C with subsequent H2 annealing at 500 °C showed a resistivity of 1.5 ×10-3 Ω·cm at room temperature and an optical transmittance of 60–80% in the vis

There is an urgent need to develop solid electrolytes based on organic molecular crystals for application in energy devices. However, the quest for molecular crystals with high Li-ion conductivity is still in its infancy. In this study, the high Li-ion conductivity of a Li{N(SO₂F)₂}(NCCH₂CH₂CN)₂ molecular crystal is reported. The crystal shows a Li-ion conductivity of 1 × 10^-4 S cm^-1 at 30 °C and 1 × 10^-5 S c

Tunneling spectroscopy of atomic-scale dangling-bond wires on a hydrogen-terminated Si(100)–2×1–H surface is studied using ultrahigh-vacuum scanning tunneling microscopy. Individual dangling bonds are fabricated by extracting hydrogen atoms one by one from the hydrogen terminated surface to form atomic-scale dangling-bond wires. These wires show a finite density of states at the Fermi level and do not show semiconductive band gaps. The results are compared with first-principles theoretical calcu