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183 results on '"Shoji, Fumiya"'

9. Existence of an exceptional reaction pathway for H3+ formation observed in collision-induced dissociation of methane ions at 1000 eV.

Author

Shoji, Fumiya, Nagai, Tatsuzo, and Morimoto, Fumio

Subjects
*CHEMICAL reactions, *DISSOCIATION (Chemistry), *COLLISIONS (Nuclear physics), *STOPPING power (Nuclear physics), *SCATTERING amplitude (Physics), *FRAGMENTATION reactions, *NUCLEAR cross sections, *ATOMIC hydrogen
Abstract

Dissociation of CH4+ ions at 1000 eV induced by collision with Ar atoms was investigated by measuring the kinetic energies of the ionized fragments. At small scattering angles, including zero, H+, H2+, H3+, CH3+, CH2+, CH+, and C+ fragments were observed. The attractive part of the potential in the CH4+-Ar collision system played an important role in the formation of the ionized fragments. Rainbow scattering, leading to a large scattering cross section, was shown to be responsible for the increased formation of H3+. It is proposed that on collision-induced dissociation of CH4+, its three hydrogen atoms, which form a triangle, simultaneously react and move together to form H3+. [ABSTRACT FROM AUTHOR]

Published
2011
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10. Evidence of dissociative collision induced diatomic and triatomic hydrogen ion formation from hydrocarbon ion interaction with silicon surface.

Author

Shoji, Fumiya

Subjects
*HYDROCARBONS spectra, *ION bombardment, *METHANE, *SPECTRUM analysis, *HYDROGEN production, *SILICON, *ION-molecule collisions
Abstract

A singly charged hydrocarbon ion CHx+ (x=0,1,2,3,4) was extracted from an electron bombardment type ion source using methane as the reagent gas and irradiated onto the Si(100) surface at glancing angle. Scattered ion spectrometry using an electrostatic energy analyzer revealed that H+, H2+, and H3+ ions were clearly formed at the scattering angle of 15°, associated with dissociative collisions of hydrocarbon ion species of incidence energy of 1000 eV. The formation of H3+ was tentatively interpreted as resulting from combination of excited atomic hydrogen produced by dissociative collisions of CH4+ ions with Si(100) surface. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2004
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13. Oxygen annealing for deuterium doped indium tin oxide thin films

Author

Okada, Koichi, Kohiki, Shigemi, Luo, Suning, Kohno, Atsushi, Tajiri, Takayuki, Ishii, Satoshi, Sekiba, Daiichiro, Mitome, Masanori, and Shoji, Fumiya

Subjects
sputtering deposition, photoelectron spectra, annealing, optical transmittance spectra, doping, indium tin oxide
Abstract

Deuterium-doped indium tin oxide films, fabricated by dc plasma deposition in sputter gas consisting of deuterium and argon, were annealed at 300 °C for 40 min in flowing oxygen gas by using tubular gold image furnace. On oxygen annealing, the optical transparency of the film deposited at the gas pressure ratio of deuterium to argon of 3.6% increased from ≈30 to 60% at the wavelength of 600 nm, although that of the films deposited at the ratios of 1 and 1.5% slightly decreased from 88 to 80% and from 85 to 77%, respectively. The resistivity of the films at room temperature, ranged from 2 × 10−4 to 1.4 × 10−3 Ω cm corresponding to the gas pressure ratio from 1 to 3.6%, was almost the same before and after the annealing for each film. A change in morphology toward a smoother surface by the oxygen annealing was apparent especially for the film with the gas pressure ratio of 3.6%. Agglomeration of randomly oriented grains with diameters of

Published
2011

14. Hydrogen effects on crystallinity, photoluminescence, and magnetization of indium tin oxide thin films sputter-deposited on glass substrate without heat treatment

Author

Luo, Suning, Kohiki, Shigemi, Okada, Koichi, Shoji, Fumiya, and Shishido, Toetsu

Abstract

Indium tin oxide (ITO) thin films were sputter deposited by using working gas containing hydrogen on glass substrate without any heat treatments. The films demonstrated X-ray diffraction due to polycrystalline ITO, blue-green photoluminescence (PL) due to oxygen defects in nano-structured ITO crystals, and paramagnetic behaviour in temperature dependence of magnetization overlapped with diamagnetic signal from the substrate. The carrier density n of the films was of the order of 1020 cm−3, and varied as an inverse of V-character with the hydrogen concentration [H] in the gas. The n value peaked at [H] = 1%. Spectral features at ≈430 and ≈470 nm of the PL emission were invariant with [H]. The order of the density of electrons N with spins obeying the Curie law was 1023 cm−3, and the variation in N with [H] was almost parallel to that in n with [H].

Published
2010

15. Effects of hydrogen in working gas for sputter-deposition on surface morphology and microstructure of indium tin oxide thin films grown at room temperature

Author

Luo, Suning, Kohiki, Shigemi, Okada, Koichi, Mitome, Masanori, and Shoji, Fumiya

Subjects
Indium tin oxide, Surface morphology, Microstructure, Hydrogen
Abstract

Surface morphology and microstructure of indium tin oxide (ITO) thin films sputter deposited without heat treatment were obviously different from each other depending on the hydrogen concentration [H] in the working gas. The film surface became smoother with increasing [H] to 1%, but nucleation and growth of grains were apparent above [H] = 1.5%. The width of columnar grains in the ≤200 nm-thick films narrowed from ≈100 nm to ≈50 nm with increasing [H] from 0% to 1.5%. Randomly oriented and agglomerated grains were observed for the film deposited with [H] = 3.6%. Hydrogen added to the working gas induced reduction of the grain size, and then resulted in lowering of the carrier mobility.

Published
2009

16. Optical and electrical properties of indium tin oxide thin films sputter-deposited in working gas containing hydrogen without heat treatments

Author

Luo, Suning, Okada, Koichi, Kohiki, Shigemi, Tsutsui, Fuki, Shimooka, Hirokazu, and Shoji, Fumiya

Subjects
Optical transmittance, Carrier transport, Indium tin oxide, Hydrogen
Abstract

Polycrystalline thin films of indium tin oxide sputter-deposited in the working gas containing hydrogen of 0.3–1.5% exhibited transmittance of ≥ 80% for visible lights and blue-shift of ≥ 0.1 eV in the optical absorption energy. The film deposited in the gas containing hydrogen of 1% demonstrated almost flat temperature-dependent resistivity and the lowest resistivity of ≈ 1.5 × 10− 4 Ω cm at room temperature. The carrier density showed an inverse V-shaped behavior with the maximum at the hydrogen concentration of 1%. The mobility stayed at almost constant below the hydrogen concentration of 1% and dropped rather rapidly above 1%.

Published
2009

18. Elastic recoil detection analysis of coadsorption of hydrogen and deuterium on clean Si surfaces

Author

Shoji Fumiya, Morioka Hajime, Oura Kenjiro, Watamori Michio, and Naitoh Masamichi

Subjects
In situ, Nuclear and High Energy Physics, Ion beam, Hydrogen, Ultra-high vacuum, Analytical chemistry, chemistry.chemical_element, Elastic recoil detection, Adsorption, Deuterium, chemistry, Nuclear Experiment, Instrumentation, Quantitative analysis (chemistry)
Abstract

Quantitative analysis of hydrogen and deuterium coadsorbed on clean Si(111) surfaces has been carried out by elastic recoil detection analysis using a 6 MeV F 3+ ion beam under an ultra high vacuum condition. H adsorption processes onto D-saturated Si(111) surfaces and vice versa have been studied in situ.

Published
1994

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