The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Mamoru Yoshimoto - One of the best experts on this subject based on the ideXlab platform.
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Structural analysis of InxGa1−xN single quantum wells by coaxial-impact collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 2000Co-Authors: M Sumiya, Shuji Nakamura, Shigefusa F Chichibu, K Mizuno, M Furusawa, Mamoru YoshimotoAbstract:The structures of InxGa1−xN single quantum wells (SQWs) on 3-μm-thick GaN layer for the ultraviolet, blue, and green light-emitting devices were investigated by coaxial-impact collisIon Ion Scattering Spectroscopy (CAICISS). The possibility that CAICISS could analyze structural fluctuatIon of the ternary system like InxGa1−xN was demonstrated. It was found that In incorporated into InGaN SQWs occupied the substitutIonal site of Ga atom having Ga-face (+c) polarity.
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structural analysis of inxga1 xn single quantum wells by coaxial impact collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 2000Co-Authors: M Sumiya, Shuji Nakamura, Shigefusa F Chichibu, K Mizuno, M Furusawa, Mamoru YoshimotoAbstract:The structures of InxGa1−xN single quantum wells (SQWs) on 3-μm-thick GaN layer for the ultraviolet, blue, and green light-emitting devices were investigated by coaxial-impact collisIon Ion Scattering Spectroscopy (CAICISS). The possibility that CAICISS could analyze structural fluctuatIon of the ternary system like InxGa1−xN was demonstrated. It was found that In incorporated into InGaN SQWs occupied the substitutIonal site of Ga atom having Ga-face (+c) polarity.
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in situ determinatIon of the terminating layer of la0 7sr0 3mno3 thin films using coaxial impact collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 1998Co-Authors: Mamoru Yoshimoto, T Ohnishi, H Maruta, Kenji Sasaki, Hideomi KoinumaAbstract:In situ analysis of the terminating atomic plane of c-axis oriented La0.7Sr0.3MnO3 thin films grown epitaxially on SrTiO3(100) substrate by laser molecular beam epitaxy has been carried out employing coaxial impact-collisIon Ion Scattering Spectroscopy (CAICISS). The CAICISS time-of-flight spectroscopic studies reveal that the (001) surface of c-axis oriented La0.7Sr0.3MnO3 thin films is predominantly terminated with MnO2 plane. The azimuth rotatIonal CAICISS measurements show a fourfold symmetry in the surface atom alignments establishing the square lattice structure of the terminating plane.
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determinatIon of surface polarity of c axis oriented zno films by coaxial impact collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 1998Co-Authors: Tatsuya Ohnishi, A. Ohtomo, M. Kawasaki, Mamoru Yoshimoto, Kazuhiro Takahashi, Hideomi KoinumaAbstract:We have identified the surface polar structure of wurtzite-type ZnO films by coaxial impact-collisIon Ion Scattering Spectroscopy. High-quality ZnO epitaxial films were prepared on sapphire (α-Al2O3) (0001) substrates by laser molecular beam epitaxy using a ZnO ceramic target. The (0001) crystallographic plane (the O face) was found to terminate the top surface of the ZnO film by comparing spectra of the films with those of well-defined (0001) and (0001) surfaces of bulk single crystals. The preferential [0001] growth directIon of ZnO films is discussed from the viewpoints of the chemical interactIon at the interface and surface stability against sublimatIon.
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Atomic scale identificatIon of the terminating structure of compound materials by CAICISS (coaxial impact collisIon Ion Scattering Spectroscopy)
Applied Surface Science, 1997Co-Authors: Osamu Ishiyama, Hideomi Koinuma, Shigeki Hayashi, Mamoru Yoshimoto, Makoto Shinohara, Takaharu Nishihara, Shigehiro Nishino, Tsuyoshi Ohnishi, Junji SaraieAbstract:Abstract Quantitative surface analysis includes the determinatIon of the elemental compositIon and the structure of the sample under investigatIon. Although LEED, XPS, and SPM etc. have been used to investigate the surface structure of the materials, ambiguity remains in determining quantitatively the topmost atomic species and its alignment on an atomic scale. Therefore, we adopted coaxial impact collisIon Ion Scattering Spectroscopy (CAICISS) to identify the terminating structure of compound materials such as SrTiO3(001), InP(001) etc. As a result of the measurements, we could determine the topmost atomic plane of those materials. CAICISS is considered to be a powerful tool for those topmost surface analysis of the materials.
Yasushi Yamauchi - One of the best experts on this subject based on the ideXlab platform.
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element selective spin polarizatIon analysis of surfaces by spin polarized Ion Scattering Spectroscopy
Surface Science, 2010Co-Authors: Taku Suzuki, H Kuwahara, Yasushi YamauchiAbstract:We discuss the validity of surface spin polarizatIon analysis with element selectivity using spin-polarized Ion Scattering Spectroscopy (SP-ISS). We examined the control of the incident 4He+ spins and successfully conducted magnetic hysteresis measurement on an Fe(100) surface. The spin polarizatIon of the Fe(100) surface exposed to O2 atmosphere measured by spin-polarized Ion neutralizatIon Spectroscopy was consistent with that reported by spin-polarized metastable de-excitatIon Spectroscopy. The element selectivity of SP-ISS is discussed in terms of Ion neutralizatIon, re-IonizatIon, and multiple Scattering.
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spin polarized Ion Scattering Spectroscopy of ccl4 adsorptIon on fe 001 surfaces
Surface Science, 2008Co-Authors: S Entani, Toshinori Suzuki, Yasushi YamauchiAbstract:Abstract The interactIon of CCl 4 molecules with Fe(0 0 1) surfaces was investigated by spin-polarized Ion Scattering Spectroscopy (SP-ISS). It was observed that CCl 4 molecules adsorb dissociatively on the surface at ambient temperature (∼290 K), and consequently, iron and chlorine were major surface constituents. It was found that the chlorine adatoms are located atop of iron atoms of the second surface layer (hollow sites of the surface). It is indicated that the spin state of iron atoms at the surface is not affected by exposure to a CCl 4 atmosphere, while almost no spin is induced in the chlorine adatoms. Similar behavior is observed in the spin states of iron and chlorine on an oxygen preadsorbed-Fe(0 0 1) surface. The difference in the spin states of iron and chlorine clarifies the local property of the incidence Ion neutralizatIon and element selectivity of SP-ISS in this CCl 4 /Fe system.
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spin polarized Ion Scattering Spectroscopy as a novel analytical method of magnetic structure at outermost surfaces
Surface Science, 2008Co-Authors: Taku Suzuki, Yasushi YamauchiAbstract:Abstract We developed spin-polarized Ion Scattering Spectroscopy (SP-ISS). In SP-ISS, spin-polarized 4 He + Ions are projected onto a sample surface, and the kinetic energy of scattered Ions, which survive in neutralizatIon, are analyzed. We observed that scattered Ion yield depends on spin of the incident He + Ions on an Fe(1 0 0) surface exposed to an oxygen atmosphere. Furthermore, we revealed that the spin dependence of scattered Ion yield reflects the spin state of target atoms. Thus, SP-ISS may be capable of analyzing the spin state of outermost surfaces with element selectivity.
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development of spin polarized Ion Scattering Spectroscopy
Analytical Sciences, 2008Co-Authors: Taku Suzuki, Yasushi YamauchiAbstract:Spin-polarized Ion Scattering Spectroscopy using an electron-spin-polarized 4 He + Ion beam was developed as a novel analytical method of the element selective spin state at outermost surfaces. Spin-polarized He + Ions were generated from the Penning IonizatIon of metastable He 2 3 S 1 atoms (He*), which were spin-polarized by optical pumping (OP). The spin polarizatIon of He* (P He *) was observed to be the highest with an OP radiatIon density of about 0.05 W cm -2 , and a further increase of the OP radiatIon density reduced P He* . This decrease of P He * is attributed to imperfect polarizatIon of the OP radiatIon, hence optimizatIon of the OP radiatIon density is essential to obtain He + Ions with high spin polarizatIon. As a result of this optimizatIon, we successfully observed the spin dependence of the scattered He + Ion yield on an Fe(100) surface exposed to an oxygen atmosphere.
Hideomi Koinuma - One of the best experts on this subject based on the ideXlab platform.
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in situ determinatIon of the terminating layer of la0 7sr0 3mno3 thin films using coaxial impact collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 1998Co-Authors: Mamoru Yoshimoto, T Ohnishi, H Maruta, Kenji Sasaki, Hideomi KoinumaAbstract:In situ analysis of the terminating atomic plane of c-axis oriented La0.7Sr0.3MnO3 thin films grown epitaxially on SrTiO3(100) substrate by laser molecular beam epitaxy has been carried out employing coaxial impact-collisIon Ion Scattering Spectroscopy (CAICISS). The CAICISS time-of-flight spectroscopic studies reveal that the (001) surface of c-axis oriented La0.7Sr0.3MnO3 thin films is predominantly terminated with MnO2 plane. The azimuth rotatIonal CAICISS measurements show a fourfold symmetry in the surface atom alignments establishing the square lattice structure of the terminating plane.
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determinatIon of surface polarity of c axis oriented zno films by coaxial impact collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 1998Co-Authors: Tatsuya Ohnishi, A. Ohtomo, M. Kawasaki, Mamoru Yoshimoto, Kazuhiro Takahashi, Hideomi KoinumaAbstract:We have identified the surface polar structure of wurtzite-type ZnO films by coaxial impact-collisIon Ion Scattering Spectroscopy. High-quality ZnO epitaxial films were prepared on sapphire (α-Al2O3) (0001) substrates by laser molecular beam epitaxy using a ZnO ceramic target. The (0001) crystallographic plane (the O face) was found to terminate the top surface of the ZnO film by comparing spectra of the films with those of well-defined (0001) and (0001) surfaces of bulk single crystals. The preferential [0001] growth directIon of ZnO films is discussed from the viewpoints of the chemical interactIon at the interface and surface stability against sublimatIon.
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Coaxial impact-collisIon Ion Scattering Spectroscopy analysis of ZnO thin films and single crystals
Materials Science and Engineering: B, 1998Co-Authors: Tatsuya Ohnishi, I Ohkuboa, A. Ohtomo, M. Kawasaki, Masahiko Yoshimoto, Hideomi KoinumaAbstract:Coaxial impact-collisIon Ion Scattering Spectroscopy (CAICISS) was employed to analyze the surface structure of ZnO single crystals and thin films with various thickness. Epitaxial ZnO films grown on sapphire (α-Al2O3)(0001) by laser molecular beam epitaxy was found ...
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Atomic scale identificatIon of the terminating structure of compound materials by CAICISS (coaxial impact collisIon Ion Scattering Spectroscopy)
Applied Surface Science, 1997Co-Authors: Osamu Ishiyama, Hideomi Koinuma, Shigeki Hayashi, Mamoru Yoshimoto, Makoto Shinohara, Takaharu Nishihara, Shigehiro Nishino, Tsuyoshi Ohnishi, Junji SaraieAbstract:Abstract Quantitative surface analysis includes the determinatIon of the elemental compositIon and the structure of the sample under investigatIon. Although LEED, XPS, and SPM etc. have been used to investigate the surface structure of the materials, ambiguity remains in determining quantitatively the topmost atomic species and its alignment on an atomic scale. Therefore, we adopted coaxial impact collisIon Ion Scattering Spectroscopy (CAICISS) to identify the terminating structure of compound materials such as SrTiO3(001), InP(001) etc. As a result of the measurements, we could determine the topmost atomic plane of those materials. CAICISS is considered to be a powerful tool for those topmost surface analysis of the materials.
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In Situ DeterminatIon of Terminating Atomic Plane of SrTiO 3 (001) by Coaxial Impact CollisIon Ion Scattering Spectroscopy
Advances in Superconductivity VII, 1995Co-Authors: Osamu Ishiyama, Mamoru Yoshimoto, Tatsuro Maeda, Makoto Shinohara, Fumihiko Ohtani, Hideomi KoinumaAbstract:In situ characterizatIon of the topmost surface of SrTiO3(001) was performed by means of coaxial impact collisIon Ion Scattering Spectroscopy. As a result, it was proven that the displacement of Sr atoms occurred in the surface regIon at high temperatures around 500 °C in the case of the as-supplied SrTiO3 substrates terminated with TiO2 atomic plane. Sr atoms shifted by 0.012±0.002 nm toward [001] directIon. On the other hand, no displacement was observed in the case of O2 annealed samples at 1000 °C for 10 hours. It indicated that the stable topmost surface structure was formed by the high temperature annealing in the SrTiO3 substrates.
Taku Suzuki - One of the best experts on this subject based on the ideXlab platform.
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low energy Ion Scattering Spectroscopy and reflectIon high energy electron diffractIon of native oxides on gan 0001
Japanese Journal of Applied Physics, 2017Co-Authors: Yoshihiro Irokawa, Taku Suzuki, Kazuya Yuge, Toshihide Nabatame, Koji Kimoto, T Ohnishi, Kazutaka Mitsuishi, Yasuo KoideAbstract:We investigated native oxides on GaN(0001) wafers by low-energy Ion Scattering Spectroscopy (LEIS) and reflectIon high-energy electron diffractIon (RHEED) simultaneously. As a result, azimuthal angle-resolved LEIS revealed that the surface structure of the native oxide with a thickness of ~1.1 nm showed a low sixfold symmetry. Moreover, the RHEED patterns of native oxides on GaN showed (1 × 1) surface spots, reflecting the same lattice constant of GaN regardless of the glancing angle of the incident beam. The obtained results suggest that native oxides on GaN(0001) could be either e-Ga2O3, γ-Ga2O3(111), or their mixture, with lattice-matched structures.
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element selective spin polarizatIon analysis of surfaces by spin polarized Ion Scattering Spectroscopy
Surface Science, 2010Co-Authors: Taku Suzuki, H Kuwahara, Yasushi YamauchiAbstract:We discuss the validity of surface spin polarizatIon analysis with element selectivity using spin-polarized Ion Scattering Spectroscopy (SP-ISS). We examined the control of the incident 4He+ spins and successfully conducted magnetic hysteresis measurement on an Fe(100) surface. The spin polarizatIon of the Fe(100) surface exposed to O2 atmosphere measured by spin-polarized Ion neutralizatIon Spectroscopy was consistent with that reported by spin-polarized metastable de-excitatIon Spectroscopy. The element selectivity of SP-ISS is discussed in terms of Ion neutralizatIon, re-IonizatIon, and multiple Scattering.
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spin polarized Ion Scattering Spectroscopy as a novel analytical method of magnetic structure at outermost surfaces
Surface Science, 2008Co-Authors: Taku Suzuki, Yasushi YamauchiAbstract:Abstract We developed spin-polarized Ion Scattering Spectroscopy (SP-ISS). In SP-ISS, spin-polarized 4 He + Ions are projected onto a sample surface, and the kinetic energy of scattered Ions, which survive in neutralizatIon, are analyzed. We observed that scattered Ion yield depends on spin of the incident He + Ions on an Fe(1 0 0) surface exposed to an oxygen atmosphere. Furthermore, we revealed that the spin dependence of scattered Ion yield reflects the spin state of target atoms. Thus, SP-ISS may be capable of analyzing the spin state of outermost surfaces with element selectivity.
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development of spin polarized Ion Scattering Spectroscopy
Analytical Sciences, 2008Co-Authors: Taku Suzuki, Yasushi YamauchiAbstract:Spin-polarized Ion Scattering Spectroscopy using an electron-spin-polarized 4 He + Ion beam was developed as a novel analytical method of the element selective spin state at outermost surfaces. Spin-polarized He + Ions were generated from the Penning IonizatIon of metastable He 2 3 S 1 atoms (He*), which were spin-polarized by optical pumping (OP). The spin polarizatIon of He* (P He *) was observed to be the highest with an OP radiatIon density of about 0.05 W cm -2 , and a further increase of the OP radiatIon density reduced P He* . This decrease of P He * is attributed to imperfect polarizatIon of the OP radiatIon, hence optimizatIon of the OP radiatIon density is essential to obtain He + Ions with high spin polarizatIon. As a result of this optimizatIon, we successfully observed the spin dependence of the scattered He + Ion yield on an Fe(100) surface exposed to an oxygen atmosphere.
Fumihiko Ohtani - One of the best experts on this subject based on the ideXlab platform.
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IdentificatIon of the terminating structure of 6H–SiC(0001) by coaxial impact collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 1997Co-Authors: Osamu Ishiyama, Makoto Shinohara, Fumihiko Ohtani, Takaharu Nishihara, Shigehiro Nishino, Junji SaraieAbstract:The terminating structure of 6H–SiC(0001) substrates fabricated by the Acheson method was directly identified by means of coaxial impact collisIon Ion Scattering Spectroscopy (CAICISS). The CAICISS spectra showed that the topmost surfaces of the samples were Si-terminated planes for both the front and rear faces. It was also shown that the (0001)Si face was composed of Si-terminated flat terraces and steps, the height of which corresponded to one-half the unit cell length along the 6H–SiC c axis.
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In Situ DeterminatIon of Terminating Atomic Plane of SrTiO 3 (001) by Coaxial Impact CollisIon Ion Scattering Spectroscopy
Advances in Superconductivity VII, 1995Co-Authors: Osamu Ishiyama, Mamoru Yoshimoto, Tatsuro Maeda, Makoto Shinohara, Fumihiko Ohtani, Hideomi KoinumaAbstract:In situ characterizatIon of the topmost surface of SrTiO3(001) was performed by means of coaxial impact collisIon Ion Scattering Spectroscopy. As a result, it was proven that the displacement of Sr atoms occurred in the surface regIon at high temperatures around 500 °C in the case of the as-supplied SrTiO3 substrates terminated with TiO2 atomic plane. Sr atoms shifted by 0.012±0.002 nm toward [001] directIon. On the other hand, no displacement was observed in the case of O2 annealed samples at 1000 °C for 10 hours. It indicated that the stable topmost surface structure was formed by the high temperature annealing in the SrTiO3 substrates.
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topmost surface analysis of srtio3 001 by coaxial impact collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 1994Co-Authors: Mamoru Yoshimoto, Hideomi Koinuma, Tatsuro Maeda, Kazuki Shimozono, Makoto Shinohara, Osamu Ishiyama, Fumihiko OhtaniAbstract:The terminating atomic plane of SrTiO3 (001) surface was investigated by means of coaxial impact‐collisIon Ion Scattering Spectroscopy (CAICISS). CAICISS spectra proved that SrTiO3 (001) surfaces of as‐supplied substrates as well as of O2‐annealed substrates were predominantly terminated with TiO2 atomic plane, while the SrO atomic plane came at the topmost surface of SrTiO3 (001) homoepitaxial film. This indicates the structural conversIon of the topmost atomic layer from TiO2 to SrO occurred during the SrTiO3 homoepitaxial growth. The azimuth rotatIonal CAICISS spectra exhibited a fourfold symmetry in the surface atom alignments, showing the square lattice structure of a terminating plane.
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Topmost surface analysis of SrTiO3 (001) by coaxial impact‐collisIon Ion Scattering Spectroscopy
Applied Physics Letters, 1994Co-Authors: Mamoru Yoshimoto, Hideomi Koinuma, Tatsuro Maeda, Kazuki Shimozono, Makoto Shinohara, Osamu Ishiyama, Fumihiko OhtaniAbstract:The terminating atomic plane of SrTiO3 (001) surface was investigated by means of coaxial impact‐collisIon Ion Scattering Spectroscopy (CAICISS). CAICISS spectra proved that SrTiO3 (001) surfaces of as‐supplied substrates as well as of O2‐annealed substrates were predominantly terminated with TiO2 atomic plane, while the SrO atomic plane came at the topmost surface of SrTiO3 (001) homoepitaxial film. This indicates the structural conversIon of the topmost atomic layer from TiO2 to SrO occurred during the SrTiO3 homoepitaxial growth. The azimuth rotatIonal CAICISS spectra exhibited a fourfold symmetry in the surface atom alignments, showing the square lattice structure of a terminating plane.
