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Journal Articles

Corrigendum to "Real time observation of oxygen chemisorption states on Si(001)-2$$times$$1 during supersonic oxygen molecular beam irradiation"

Teraoka, Yuden; Yoshigoe, Akitaka

Applied Surface Science, 346, P. 580, 2015/08

 Times Cited Count:0 Percentile:1.75(Chemistry, Physical)

Journal Articles

Corrigendum to "Si 2p and O 1s photoemission from oxidized Si(001) surfaces depending on translational kinetic energy of incident O$$_{2}$$ molecules"

Teraoka, Yuden; Yoshigoe, Akitaka

Applied Surface Science, 343, P. 212, 2015/07

 Times Cited Count:0 Percentile:1.75(Chemistry, Physical)

Journal Articles

Corrigendum to "Coexistence of passive and active oxidation for O$$_{2}$$/Si(001) system observed by SiO mass spectrometry and synchrotron radiation photoemission spectroscopy"

Teraoka, Yuden; Moritani, Kosuke*; Yoshigoe, Akitaka

Applied Surface Science, 343, P. 213, 2015/07

 Times Cited Count:0 Percentile:1.75(Chemistry, Physical)

Journal Articles

Comparative study of oxidation on Cu and Cu$$_{3}$$Au surfaces with a hyperthermal O$$_{2}$$ molecular beam

Okada, Michio*; Moritani, Kosuke; Fukuyama, Tetsuya*; Mizutani, Hironori*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Toshio*

Surface Science, 600(18), p.4228 - 4232, 2006/09

 Times Cited Count:20 Percentile:64.46(Chemistry, Physical)

Dissociative adsorption of hyperthermal O$$_{2}$$ molecules on Cu$$_{3}$$Au(100) was investigated by X-ray photoemission spectroscopy in conjunction with a synchrotron light source. Comparing the O-uptake curve on Cu$$_{3}$$Au with that on Cu, it was found that the dissociative adsorption of O$$_{2}$$ is more activated (less reactive) due to Au alloying. The low-energy electron-diffraction (LEED) pattern of c(2$$times$$2) for the clean surface turned into the (1$$times$$1) LEED pattern during the oxidation by hyperthermal O$$_{2}$$ molecular beam, suggesting that the O adsorption induces the Cu-atom segregation on the surface.

Journal Articles

Structure of GaAs(001)-c(4$$times$$4); Comparison of X-ray diffraction and first-principles calculation

Takahashi, Masamitsu; Kratzer, P.*; Penev, E.*; Mizuki, Junichiro

Surface Science, 600(18), p.4099 - 4102, 2006/09

 Times Cited Count:1 Percentile:6.64(Chemistry, Physical)

The GaAs(001)-c(4$$times$$4) has been studied by synchrotron surface X-ray diffraction. The atomic coordinates and Debye-Waller factors were determined up to the sixth layer from the surface. The results support the formation of the Ga-As heterodimers. The resultant atomic coordinates were compared with those given by a first-principle calculation. In spite of the theoretical prediction of the stability of the single-heterodimer structure, our data fit best a three-heterodimer model where three heterodimers are present in one unit cell. The preference of the formation of the three heterodimers will be discussed in the relationship with the transition process from the 2$$times$$4 to the c(4$$times$$4) structures.

Journal Articles

Oxidation reaction kinetics on Ti(0001) surface studied by real-time photoelectron spectroscopy

Takakuwa, Yuji*; Ogawa, Shuichi*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden

Shokubai, 47(5), p.352 - 357, 2005/08

Oxidation reactions of Ti(0001) surfaces were monitored by real-time photoelectron spectroscopy with high brilliant synchrotron radiation and He-I resonance line. An oxygen adsorption model and ultra-thin oxide layers formation processes were reviewed on the basis of time evolutions of the adsorbed oxygen amount, oxidation states, electronic states and the work function, which were obtained from photoelectron spectra for Ti 2p and O 1s core levels as well as the valence band.

Journal Articles

Full characterization of an intense pulsed hyperthermal molecular beam

Watanabe, Daisuke*; Che, D.-C.*; Fukuyama, Tetsuya*; Hashinokuchi, Michihiro*; Teraoka, Yuden; Kasai, Toshio*

Review of Scientific Instruments, 76(5), p.055108_1 - 055108_5, 2005/05

 Times Cited Count:6 Percentile:33.46(Instruments & Instrumentation)

A molecular beam technique for generating an intense pulsed hyperthermal molecular beam (HTMB) was developed. The beam source consists of a pulse valve, a cooling-water bottle that protectes the pulse valve from heat transfer of a high temperature nozzle, and the nozzle with a heater. The pulsed HTMB of HCl was practically generated and characterized by means of (2+1) resonance-enhanced multiphoton ionization and ion time-of-flight techniques.

JAEA Reports

Manufacture of high-speed neutral atomic and molecular beam apparatus and its characterization

Hachiue, Shunsuke; Teraoka, Yuden

JAERI-Tech 2004-066, 69 Pages, 2004/11

JAERI-Tech-2004-066.pdf:7.44MB

In order to progress chemical reaction studies at verious material surfaces using high speed and reactive ions and neutral particles beams, a high-speed neutral atomic and molecular beam apparatus has been developed. In this report, details of the apparatus and characteristics of actually-generated oxygen atomic and molecular ion/neutral beams are discribed. This apparatus is a ultra-high vacuum system consisting of a plasma ion source, electrostatic lens systems, a mass separator, and a charge transfer chamber. Total oxygen ion currents of 52 microamps at accerelation energy of 8 keV and 17 microamps even at 20 eV were obtained. Mass separation was also good so that an oxygen molecular ion beam of 11 microamps and an oxygen atomic ion beam of 5.5 microamps were obtained even at 20 eV. A neutral oxygen atomic or molecular beam was also generated with the flux density of 10$$^{12}$$ particles/cm$$^{2}$$/s.

Journal Articles

X-ray diffraction study on GaAs(001)-2$$times$$4 surfaces under molecular-beam epitaxy conditions

Takahashi, Masamitsu; Yoneda, Yasuhiro; Mizuki, Junichiro

Applied Surface Science, 237(1-4), p.219 - 223, 2004/10

 Times Cited Count:5 Percentile:29.77(Chemistry, Physical)

The GaAs(001)-$$(2times4)$$ reconstructed surface was investigated by in situ surface X-ray diffraction. The sample was subjected to measurements under molecular-beam epitaxy conditions without being transferred another chamber. Several X-ray diffraction patterns were measured with increasing the substrate temperature within the $$beta$$-phase of GaAs(001)-$$(2times4)$$ in a constant As flux of 5$$times$$10$$^{-7}$$ Torr. At relatively low temperatures up to 545$$^circ$$C, the observed X-ray diffraction patterns agree well to the $$beta$$2(2$$times$$4) surface. However, a different X-ray diffraction pattern was obtained at 585$$^circ$$C, while the $$2times 4$$ periodicity still persited. This change is explained by partial As-dimer desorption which results in a mixture of the $$beta$$2(2$$times$$4) and $$alpha$$2(2$$times$$4) structures.

Journal Articles

Photoemission study of the translational energy induced oxidation processes on Cu(111)

Moritani, Kosuke; Okada, Michio*; Sato, Seiichi*; Goto, Seishiro*; Kasai, Toshio*; Yoshigoe, Akitaka; Teraoka, Yuden

Journal of Vacuum Science and Technology A, 22(4), p.1625 - 1630, 2004/08

 Times Cited Count:25 Percentile:66.06(Materials Science, Coatings & Films)

We studied the oxidation of Cu{111} surface with a hyperthermal O$$_{2}$$ molecular beam (HOMB) using X-ray photoemission spectroscopy (XPS) in conjunction with a synchrotron radiation (SR) source. The efficiency of oxidation with 0.6-eV-HOMB is higher thab that with 2.3-eV-HOMB under $$theta$$ $$leq$$ 0.5ML. Ont the other hand, further oxidation occurs rather inefficiency under $$theta$$ $$geq$$ 0.5ML. In this region, efficiency of oxidation with 2.3-eV-HOMB is higher than 0.6-eV-HOMB. We found that such slow oxidation process of Cu can be interpreted in terms of a collision-induced-adsorption mechanism. These results suggest that we can control the oxidation process of Cu by using HOMB.

JAEA Reports

Initial oxidation of Ti(0001) surfaces induced by supersonic oxygen molecular beams

Ogawa, Shuichi*; Takakuwa, Yuji*; Ishizuka, Shinji*; Mizuno, Yoshiyuki*; Tonda, Hideki*; Homma, Teiichi*; Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke; Hachiue, Shunsuke

JAERI-Tech 2004-046, 25 Pages, 2004/06

JAERI-Tech-2004-046.pdf:2.51MB

We investigated the correlation between initial sticking coefficient and O$$_{2}$$ transitional kinetic energy to understand O$$_{2}$$ adsorption processes on the Ti(0001) surface via photoemission spectroscopy for O-1s and Ti-2p core levels using the surface reaction analysis apparatus, installed at the JAERI soft X-ray beamline BL23SU in the SPring-8. We observed the decrease of initial sticking coefficient of O$$_{2}$$ molecules on the Ti(0001) surface with increasing O$$_{2}$$ transitional kinetic energy. We concluded that the O$$_{2}$$ adsorption on the Ti(0001) surface proceeded by a trapping-mediated dissociative adsorption mechanism. The constant dependence of the initial sticking coefficient on incident angle of O$$_{2}$$ beams also suggested the propriety of the trapping-mediated surface reaction mechanism.

Journal Articles

Actively controlled oxidation of Cu{001} with hyperthermal O$$_{2}$$ molecular beam

Okada, Michio*; Moritani, Kosuke; Goto, Seishiro*; Kasai, Toshio*; Yoshigoe, Akitaka; Teraoka, Yuden

Journal of Chemical Physics, 119(14), p.6994 - 6997, 2003/10

 Times Cited Count:42 Percentile:78.24(Chemistry, Physical)

The oxidation of Cu(001) with hyperthermal O$$_{2}$$ molecular beams was investigated using X-ray photoemission spectroscopy in conjunction with a synchrotron light source. The efficiency of oxidation is higher than that with ambient thermal O$$_{2}$$. Further oxidation under oxygen coverage larger than 0.5 ML occurs rather inefficiently even for the 2.3 eV beam irradiation. We found such slow oxidation of Cu corresponding to the initial stage of the Cu$$_{2}$$O formation can be interpreted in terms of a collision-induced-adsorption mechanism. The kinetics of the dissociative adsorption is well described using the first order kinetics in a simple Langmuir-type adsorption model.

Journal Articles

Oxidation of aqueous HF-treated Si(001) surface induced by translational kinetic energy of O$$_{2}$$ at room temperature

Yoshigoe, Akitaka; Teraoka, Yuden

Japanese Journal of Applied Physics, Part 1, 42(9A), p.5749 - 5750, 2003/09

 Times Cited Count:2 Percentile:10.73(Physics, Applied)

We investigated oxidation reactions induced by the translational kinetic energy of O$$_{2}$$ on an Si(001) surface treated with aqueous hydrofluoric acid (HF) solution by combining synchrotron radiation photoemission spectroscopy with supersonic molecular beam techniques. The oxidation reactions at room temperature did not progress following up to approximately 3600 L exposure of O$$_{2}$$ with incident energy of 0.04 eV. On the other hand, the oxidation states up to the Si$$^{4+}$$ species including the Si$$^{1+}$$, Si$$^{2+}$$ and Si$$^{3+}$$ species were formed when the incident energy was 3.0 eV. The thickness of oxidized layers was estimated to be 0.26 nm at the final oxidation stages. Thus, we concluded that the Si atoms at the top layers were oxidized by the translational kinetic energy of 3.0 eV.

Journal Articles

SiO mass spectrometry and Si-2p photoemission spectroscopy for the study of oxidation reaction dynamics of Si(001) surface by supersonic O$$_{2}$$ molecular beams under 1000 K

Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke

Japanese Journal of Applied Physics, Part 1, 42(7B), p.4671 - 4675, 2003/07

 Times Cited Count:4 Percentile:20.13(Physics, Applied)

The oxidation reaction mechanisms for Si(001) by O$$_{2}$$ molecules have been investigated in a surface temperature region from 860 K to 1300 K and in an incident energy region from 0.6 eV to 3.0 eV. Synchrotron Radiation photoemission spectroscopy was used for surface analysis. Si-2p photoemission spectra were measured during molecular beam irradiation so that their dependences on surface temperature and incident energy were clarified. SiO molecules, desorbed from the surface at high temperature region, were also detected by a quadrupole mass analyzer using $$^{18}$$O$$_{2}$$ molecular beams to measure SiO desorption yield depending on surface temperature and incident energy. Consequently, a reaction scheme, oxide layers formation, etching, and coexistence of both reactions, is determined by the incident energy under 1000 K.

Journal Articles

Time-resolved X-ray diffraction study on surface structure and morphology during molecular beam epitaxy growth

Takahashi, Masamitsu; Yoneda, Yasuhiro; Inoue, Hirotane*; Yamamoto, Naomasa*; Mizuki, Junichiro

Journal of Crystal Growth, 251(1-4), p.51 - 55, 2003/04

 Times Cited Count:3 Percentile:22.02(Crystallography)

The reflection high energy electron diffraction (RHEED) oscillation has been widely adopted for studies on growth kinetics and dynamics in molecular beam epitaxy (MBE). Recent development in brilliant X-ray source has enabled similar experiments with X-rays, which has great advantage in a straightforward interpretation of results and in a high angular resolution. In general, the diffracted intensity from surface is proportional to the surface structure factor associated with the surface reconstruction, F, multiplied by a damping factor associated with the surface roughness, m. We show that the two factors, F and m, can be obtained separately by measuring diffuse scattering around the two-dimensional Bragg peak during growth.

Journal Articles

In-situ photoemission spectroscopy for chemical reaction dynamics study of Si(001) oxidation by using high-energy-resolution synchrotron radiation

Teraoka, Yuden; Yoshigoe, Akitaka

Oyo Butsuri, 71(2), p.1523 - 1527, 2002/12

The translational kinetic energy of incident molecules is an important parameter for the study of surface chemical reaction mechanisms. New adsorption reactions, induced by the O$$_{2}$$ translational kinetic energy of several eV, have been found in the O$$_{2}$$/Si(001) system by applying the surface photoemission spectroscopy with supersonic molecular beam techniques and the high-energy-resolution synchrotron radiation. The termination of dangling bonds affected dominantly the oxidation of dimer backbonds. By controlling the translational kinetic energy of incident O$$_{2}$$ molecules, the formation of oxide-layers with a sub-nanometer scale is possible at room temperature.

Journal Articles

X-ray diffractometer for studies on molecular-beam-epitaxy growth of III-V semiconductors

Takahashi, Masamitsu; Yoneda, Yasuhiro; Inoue, Hirotane*; Yamamoto, Naomasa*; Mizuki, Junichiro

Japanese Journal of Applied Physics, Part 1, 41(10), p.6247 - 6251, 2002/10

 Times Cited Count:55 Percentile:85.24(Physics, Applied)

An X-ray diffractometer connected with a molecular-beam epitaxy (MBE) system has been constructed for in situ studies on the growing surfaces of III-V compound semiconductors. This diffractometer is based on the (4+2) type and equipped with an axis for rotating the receiving slit about the normal of the slit plane. This additional axis is used to align the resolution of the receiving slit properly for the surface X-ray diffraction measurement. For the alignment of the sample and the whole setup with respect to the X-ray beam, an XYZ-stage and an adjustable base plate are available. X-rays enter and leave the chamber through two cylindrical Be windows welded onto the MBE chamber. A graphite sheet which can be heated up to 250$$^circ$$C is placed along the inside of the Be windows to protect the Be windows from being coated with evaporated materials. Preliminary data are presented to demonstrate the feasibility of static and dynamic measurements of growing surfaces using this instrument.

Journal Articles

Reaction dynamics of Si(001) oxidation at room temperature induced by supersonic O$$_{2}$$ molecular beams

Teraoka, Yuden; Yoshigoe, Akitaka

Hyomen Kagaku, 23(9), p.553 - 561, 2002/09

no abstracts in English

Journal Articles

${it Real-time}$ observation of oxidation states on Si(001)-2$$times$$1 during supersonic O$$_{2}$$ molecular beam irradiation

Yoshigoe, Akitaka; Teraoka, Yuden

Atomic Collision Research in Japan, No.27, p.80 - 82, 2001/00

no abstracts in English

36 (Records 1-20 displayed on this page)