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.

Internal friction of vacuum‐deposited silver films

Abstract: Internal friction of vacuum‐deposited silver films 2–4 μm thick was measured using the vibrating‐reed method below room temperature in the frequency range 100–400 Hz. Two distinct relaxation peaks were observed, one at around 50 K and the other at around 140 K. The former has been identified as the Bordoni peak, which was very stable against annealing at temperatures as high as 500 °C. The latter is considered as one of the Hasiguti peaks, which completely disappeared through annealing at 400 °C.

On the field effect of the electrical conductance of discontinuous thin metal films

Abstract: In the activated tunneling model of electrical conductance of discontinuous thin metal films, non‐Ohmic conductance has thus far been explained by a field‐dependent activation energy at a high electric field. We point out that this interpretation is not appropriate. Alternatively, the field effect should be ascribed to the non‐Ohmicity of the tunneling current density at a high electric field. Results of the computation are presented.

Superstructures and Growth Properties of Indium Deposits on Silicon (111) Surfaces with Its Influence on Surface Electrical Conduction

Abstract: A molecular beam of indium is deposited on both clean and In-predeposited substrates of Si(111) at room temperature. Effects of the substrate surface on the structure of the deposits have been investigated by RHEED and conductance measurement. On the surface of Si(111)√3×√3-In, indium deposits grow two-dimensionally up to a few monolayers forming Si(111)2-In and Si(111)5×5-In, and then they begin to form epitaxial islands. On the Si(111)7×7 surfaces, no superstructures are produced and the deposits exhibit an island growth from the beginning. The surface conductance of silicon increases only when two-dimensional growth occurs.

Thin Film Materials: Stress, Defect Formation and Surface Evolution

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.

Electrical and optical properties of TiO2 anatase thin films

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.

Ultrafine metal particles

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.

Surface-enhanced Raman scattering

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.