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Akira Kinbara

Bio: Akira Kinbara is an academic researcher from University of Tokyo. The author has contributed to research in topics: Thin film & Sputtering. The author has an hindex of 26, co-authored 116 publications receiving 2211 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, the optical effect of the substrate on the anomalous absorption of aggregated silver films is taken into account in terms of the dipole interaction between an island particle and its mirror image in the substrate.

326 citations

Journal ArticleDOI
TL;DR: In this paper, the structural properties of the films were analyzed by x-ray diffractometry and the influence of total pressure, oxygen mole fraction in the mixture of Ar-O2, discharge current, and substrate temperature on structural properties were studied.
Abstract: We have been investigating the growth of crystalline titanium dioxide films at deposition temperature between room temperature and about 400 °C. The films were prepared by a dc magnetron reactive sputtering on glass and Si(100) substrates. The structural properties of the films were analyzed by x‐ray diffractometry. The influence of total pressure, oxygen mole fraction in the mixture of Ar–O2, discharge current, and substrate temperature on the structural properties were studied. In addition to higher substrate temperature, low total pressure, high discharge current, and small oxygen mole fraction were shown to be preferable for growing anatase–rutile mixture films. Annealing of the films in air at 850 °C showed that anatase–rutile transformation strongly depends on the deposition temperature; the films deposited at temperature below 400 °C were converted to the anatase–rutile mixture films, and the films deposited at 400 °C to complete rutile films.

124 citations

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TL;DR: In this article, the average internal stress measured by the cantilever method was 5 x 108N m−2 compression, and the dependence of the size of the wrinkles on the film thickness was deduced and compared with experimental results.

109 citations

Journal ArticleDOI
TL;DR: In this article, a simple equation for the anisotropic dielectric constant of a metal island film is derived and applied to the ellipsometric measurement for an aggregated silver film.

89 citations

Journal ArticleDOI
TL;DR: In this paper, a modification of Schopper's model is proposed, based on the assumption that an aggregated film consists of particles in the shape of rotational ellipsoids.
Abstract: For interpreting the optical properties of aggregated metal films, a modification of Schopper’s model is proposed, based on the assumption that an aggregated film consists of particles in the shape of rotational ellipsoids. Instead of the distribution of the depolarizing factor f in gaussian fashion, which is assumed in Schopper’s model, the logarithmic normal distribution of the axial ratio γ of the ellipsoidal particles was assumed and the parameter σ (standard deviation of the distribution function) was introduced. Besides, the contributions of the dipole interaction between particles and the size-dependent optical constants of the particles were taken into account. Using this modified model, the observed values of silver films continuously measured by ellipsometry during deposition were analyzed and the two parameters, the mean axial ratio γ¯ and the standard deviation σ, were obtained as functions of film thickness. The results showed that as film grows, both γ¯ and σ increase monotonically. Good coincidence of the observed and the calculated absorption spectra from our model seems to show the validity of our modification.

85 citations


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Book
02 Feb 2004
TL;DR: The role of stress in mass transport is discussed in this article, where the authors consider anisotropic and patterned films, buckling, bulging, peeling and fracture.
Abstract: 1. Introduction and overview 2. Film stress and substrate curvature 3. Stress in anisotropic and patterned films 4. Delamination and fracture 5. Film buckling, bulging and peeling 6. Dislocation formation in epitaxial systems 7. Dislocation interactions and strain relaxation 8. Equilibrium and stability of surfaces 9. The role of stress in mass transport.

1,562 citations

Journal ArticleDOI
TL;DR: In this article, the metastable phase anatase has been shown to have a wider optical absorption gap than rutile thin films, which is consistent with the high mobility, bandlike conduction observed in anatase crystals.
Abstract: Electrical and optical spectroscopic studies of TiO2 anatase thin filmsdeposited by sputtering show that the metastable phase anatase differs in electronic properties from the well‐known, stable phase rutile. Resistivity and Hall‐effect measurements reveal an insulator–metal transition in a donor band in anatase thin films with high donor concentrations. Such a transition is not observed in rutile thin films with similar donor concentrations. This indicates a larger effective Bohr radius of donor electrons in anatase than in rutile, which in turn suggests a smaller electron effective mass in anatase. The smaller effective mass in anatase is consistent with the high mobility, bandlike conduction observed in anatase crystals. It is also responsible for the very shallow donor energies in anatase. Luminescence of self‐trapped excitons is observed in anatase thin films, which implies a strong lattice relaxation and a small exciton bandwidth in anatase. Optical absorption and photoconductivity spectra show that anatase thin films have a wider optical absorption gap than rutile thin films.

1,560 citations

Journal ArticleDOI
TL;DR: In this paper, a statistical growth model based on the Central Limit Theorem has been formulated for liquid-like coalescence of particles; this theory accounts satisfactorily for all the data, as well as for most size distributions published in the literature.
Abstract: In this paper we present a novel and versatile t e c h n i q u e f o r t h e p r o d u c t i o n o f u l t r a f i n e m e t a l p a r t i c l e s by evaporation from a temperature‐regulated oven containing a reduced atmosphere of an inert gas. An extensive investigation of particles of oxidized Al, with diameters of 3 to 6 nm, has been performed. We have also studied ultrafine particles of Mg,Zn, and Sn produced in the same manner. A supplementing investigation has been carried out for particles of Cr, Fe, Co, Ni, Cu, and Ga, as well as larger Al particles, produced by ’’conventional’’ inert‐gas evaporation from a resistive filament. Diameter as a function of evaporation rate, inert‐gas pressure, and the kind of inert gas are reported. Crystalline particles smaller than 20 nm look almost spherical in the electron microscope, while larger ones often display pronounced crystal habit. S i z e d i s t r i b u t i o n s have been investigated in detail, and consistently the logarithm of the particle diameter has a Gaussian distribution to a high precision for the smallest sizes, whereas larger particles deviate from such a simple behavior. A statistical growth model, based on the Central Limit Theorem, has been formulated for liquidlike coalescence of particles; this theory accounts satisfactorily for all our data, as well as for most size distributions published in the literature. Applications of the model to colloids, discontinuous films, and supported catalysts are discussed. By comparing size distributions for particles produced by a variety of techniques we found a number of empirical rules for the width of the distributions, as defined by a (geometric) standard deviation σ. For crystalline inert‐gas‐ evaporated particles we obtained consistently 1.36?σ?1.60; for coalescing islands in discontinuous films we found 1.22?σ?1.34; and similar rules are applicable to colloids, supported catalysts, and to ultrafine droplets.

1,483 citations

Journal ArticleDOI
TL;DR: In this article, the authors developed a surface-enhanced Raman scattering (SERS) model of adsorbates on metal surfaces, where the long-range enhancement by resonances of the macroscopic laser and Stokes field is separated quantitatively from the metal electron-mediated resonance Raman effect.
Abstract: On the basis of different types of experiments, the authors develop implicitly the model of surface-enhanced Raman scattering (SERS) of adsorbates on metal surfaces. The long-range enhancement by resonances of the macroscopic laser and Stokes field is separated quantitatively from the metal electron-mediated resonance Raman effect. The latter mechanism proceeds by increased electron-photon coupling at an atomically rough surface and by temporary charge transfer to orbitals of the adsorbates. This model can account for the chemical specificity and vibrational selectivity of SERS and (partly) for the SERS specificity of the various metals.

1,312 citations

Journal ArticleDOI
TL;DR: In this article, the basic physics and applications of planar metamaterials, often called metasurfaces, which are composed of optically thin and densely packed planar arrays of resonant or nearly resonant subwavelength elements, are reviewed.

1,047 citations