Search Results - (Author, Cooperation:T. Yasuda)

2014-05-17

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; B-Lymphocytes/metabolism ; CARD Signaling Adaptor Proteins/genetics/*metabolism ; Cell Line ; Chickens ; Feedback, Physiological ; Guanylate Cyclase/genetics/*metabolism ; I-kappa B Kinase/*metabolism ; MAP Kinase Kinase Kinases/genetics/*metabolism ; Mice ; Mice, Knockout ; Mutation ; NF-kappa B/*agonists ; Phosphorylation ; Receptors, Antigen, B-Cell/genetics/*metabolism ; Serine/genetics/metabolism ; Signal Transduction

1744-313X

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

An example of red cells having no reaction with any Rh antisera was found in a Japanese woman. Results of a serological investigation of the family indicated the action of a ‘regulator’ gene. Her serum contained an antibody which agglutinated all cells of common Rh types, except for Rhnull, by the saline, anti-globulin and papain techniques.

Electronic Resource

2018-02-27

Wiley-Blackwell

1525-2027

Chemistry and Pharmacology

Geosciences

Physics

1089-7550

AIP Digital Archive

Physics

This article reports a selective-area deposition process using chlorosilane-treated ultrathin SiO2 masks on which the patterns are directly defined by irradiation of a focused electron beam (EB). Three different chlorosilane gases (SiH2Cl2, SiHCl3, and SiCl4) were first adsorbed on the SiO2 surfaces, and the regions with reactive sites were defined by taking advantage of electron-stimulated desorption (ESD) of the surface adsorbates. For the SiHCl3- and SiH2Cl2-treated surfaces, the nucleation density was remarkably high in the EB-irradiated regions. Such nucleation enhancement was less significant for the SiCl4-treated surface. For the purpose of direct patterning and selective growth, we conclude that SiHCl3 is the optimum treatment gas because it effectively suppresses Si nucleation outside of the EB-irradiated patterns. The overall ESD sensitivity of the SiHCl3-adsorbed mask was 50 mC/cm2, and a significant nucleation enhancement was observed by irradiation of 7 mC/cm2. We also report an extension of this selective-area processing to window opening through the ultrathin SiO2 mask layer. The factors limiting the minimum feature size of the grown Si structures and the opened windows are discussed. © 2001 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We have investigated the nucleation processes in chemical vapor deposition (CVD) of Si on SiO2 surfaces that were treated with different chlorosilane gases SiHnCl4−n, where n=0, 1, or 2. These gases chemisorb on the SiO2 surface in a self-limiting manner. At 493 K, the saturation coverage was reached at 4×108 L exposure for the SiH2Cl2 gas, and at 2×109 L for the SiHCl3 and SiCl4 gases. CVD of Si was carried out on the chlorosilane-saturated SiO2 surfaces using Si2H6 as a source gas at 853 K. It has been found that the SiCl4 and SiHCl3 treatments effectively passivate the nucleation centers on the SiO2 surfaces, while the SiH2Cl2 treatment drastically enhances Si nucleation. The reaction mechanisms causing these differences are discussed, considering the structural changes of the adsorbed chlorosilane fragments at the CVD temperature. Application of the SiCl4 treatment to the patterned SiO2 mask for selective-area epitaxial growth of Si is demonstrated. © 2001 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Existence of Zn-As and Ga-Se interfacial layers were suggested by transmission electron microscopy in Zn treated and Se treated or reacted ZnSe/GaAs interfaces, respectively. High densities of As precipitates and Shockley partials were introduced in films with Zn treatment on a c(4×4) As-rich GaAs surface. In addition, high densities of vacancies and Shockley partials were obtained in samples with a Se-reacted ZnSe/GaAs interface. Formation of the Shockley partials may originate from the stacking errors induced by disordering of Zn- or Ga-interstitials on the GaAs surface. © 1996 American Institute of Physics.

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1077-3118

AIP Digital Archive

Physics

Low-resistivity p-type ZnSe layers have been successfully grown on GaAs substrates by metalorganic vapor phase epitaxy with the use of dimethylzinc and diethylselenide as source materials and lithium nitride as the dopant. The lowest resistivity achieved is 0.2 Ω cm, and the highest carrier concentration is 9×1017 cm−3. ZnSe p-n diodes fabricated by this technique have shown blue emission; the spectral peak is located at 467 nm.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

In this letter, we report our study on an oxide-nitride-oxide (ONO) heterostructure as a dielectric material in a metal-insulator-semiconductor field-effect transistor with Si as a semiconductor. The electrical properties of the ONO dielectrics have been correlated with: (i) the process related effects; (ii) the accumulation of N atoms and its bonding with Si at the SiO2/Si interface; and (iii) the chemical bonding within the nitride layers. By combining the remote plasma enhanced chemical vapor deposition and the rapid thermal annealing process, the device quality ONO structure with an oxide equivalent thickness of 4.7 nm has been successfully manufactured.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Chemical composition of the gas phase during the diamond growth by a hot-filament method was measured gaschromatographically for two different configurations with feed gas introduction, the conventional method from a nozzle equipped on a reactor wall and the jet feed from a hole bored in a substrate located just beneath the filament. CH4 and C2H2, diluted in H2, were used as a source gas. The results indicated that equilibration took place so rapidly near the filament that even the jet-feed mixture was converted to a thermodynamically stable composition composed mainly of C2H2, H, and H2. Insensitivity of the diamond process to the source hydrocarbon and its sensitivity to the filament-and-substrate configuration can be well interpreted.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

SiO2/Si(100) interfaces have been prepared by a low-temperature, 200–300 °C, remote plasma-assisted oxidation-deposition process. The oxidation: (i) creates ∼0.5 nm of SiO2; (ii) removes residual C from an otherwise H-terminated Si surface; and (iii) produces a SiO2/Si interface with a midgap trap density of ∼1×1010 cm−2 eV−1, and when combined with remote plasma-enhanced chemical vapor deposition (RPECVD) of SiO2, (iv) forms a SiO2/Si structure with properties comparable to those prepared by thermal oxidation of Si at 850–1050 °C.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report the intermittent photoluminescence of ZnCdSe quantum dots (QDs) embedded in a ZnSe matrix grown by molecular beam epitaxy. The luminous time of the QD is strongly dependent on temperature but not on excitation intensity. This indicates that the ionization of the QDs is determined predominantly by thermal excitation of carriers into the ZnSe matrix. © 1998 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Zinc coverage and the structures of Zn-exposed As-stabilized GaAs(001)-(2×4) and -c(4×4) surfaces have been studied using x-ray photoelectron spectroscopy and scanning tunneling microscopy in order to clarify the role of the Zn pre-exposure process in ZnSe growth on GaAs(001). Since Zn atoms stick on the GaAs-(2×4) surface even though their interaction is very weak, Zn may act as a balancer to form a neutral ZnSe/GaAs interface. Zn can also remove excess As atoms and make a "pure" (2×4) structure that is the only possible starting surface for low-defect ZnSe heteroexpitaxy on a GaAs(001) surface. © 1998 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Thin ZnSe films were grown by molecular beam epitaxy on Zn exposed (2×4) As-stabilized surfaces of GaAs epilayers under varied beam flux ratios. A very low density of faulted defects in the range of ∼ 104/cm2 was generated in samples grown under a condition with a mixture of both (2×1) and weak c(2×2) surface reconstructions at the initial stages of growth. However, an asymmetric distribution on the densities of extrinsic cation- and anion-terminated Shockley-type stacking faults were generated, respectively, in samples grown under Zn- and Se-rich surface stoichiometries. © 1996 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

An almost 100% activation ratio {(NA-ND)/[N]} for a nitrogen-doped ZnSe molecular beam epitaxy (MBE) layer with the highest net acceptor concentration (NA-ND) of 1.2×1018 cm−3 was obtained using a high-power rf plasma source. Even at this high NA-ND value, a 4.2 K photoluminescence spectrum shows bound exciton emission and deep donor–acceptor pair emission with well-resolved phonon replicas. The high activation in nitrogen doping could be ascribed to the generation of the predominant atomic nitrogen and to the suppressed extraction of nitrogen ions and excited neutral nitrogen molecules due to the structure of the orifice placed between the MBE growth chamber and the plasma discharge tube of the high-power plasma source. © 1997 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Excited neutral nitrogen species emitted from a rf plasma source were characterized by the laser-induced fluorescence (LIF) spectroscopy, while nitrogen ions were detected by the ion counting method. The LIF intensity for nitrogen molecules increases monotonously up to the rf power of 100 W and saturates over 100 W. On the contrary, ion count of nitrogen ions shows a gradual increase up to 100 W, then rapidly increases above 100 W. The correlation between the number of excited nitrogen species and the net acceptor concentration (NA−ND) of nitrogen doped ZnSe epitaxial layers for various rf powers has been studied. We confirm that the excited neutral nitrogen molecules are effective for acceptor doping, while nitrogen ions enhance carrier compensation presumably due to degradation of crystal quality. We show that the activation ratio {(NA−ND)/[N]} of p-ZnSe:N is greatly improved by removing ions from the nitrogen plasma. © 1997 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Highly luminescent ZnSe quantum dot arrays (QDAs) are spontaneously formed on cleavage-induced GaAs (110) surfaces. The QDAs are configured for their preferred growth on the step top. The confinement on carriers results from the difference in the band gaps of the strained ZnSe layer and the strain-relaxed ZnSe QDA. In contrast to other emissions from the ZnSe layer, the linewidth of the QDA emission is dependent neither on temperature nor on excitation intensity. Moreover, the energy position of the QDA emission is stable even at high excitations. These results reflect the δ functionlike density of states of the QDAs. This letter suggests a novel approach to semiconductor QDs and QDAs. © 1997 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We successfully realized ZnCdSe quantum dots on a cleavage-induced ZnSe (110) surface by depositing a ZnSe/ZnCdSe/ZnSe heterostructure under growth conditions that cannot lead to layer-by-layer growth of ZnSe. This growth mode introduces surface roughness to the newly deposited ZnSe layer, and ZnCdSe quantum dots are then formed. Cathodoluminescence and microphotoluminescence measurements demonstrate the formation of quantum dots. © 1997 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We have developed a technique to form Si microstructures at preassigned positions on Si substrates. The key element of this technique is resistless patterning of ultrathin SiO2 mask layers by direct electron-beam exposure. Selective-area growth of Si was accomplished by two different chemistries: flow-modulated plasma-enhanced chemical vapor deposition (CVD) at 473 K or ultra-high-vacuum CVD at 853 K. Epitaxial deposition was achieved by the latter growth method when a mask layer with minimum thickness for deposition selectivity (approximately 0.2 nm) was employed. © 1999 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Magnitudes of strain in ZnO epitaxial layers grown on sapphire(0001) substrates under various growth conditions were experimentally determined by x-ray diffraction. We discuss the strain-induced energy shift on the exciton resonances, the results of which were analyzed theoretically using the Hamiltonian for the valence bands under in-plain biaxial strain. Comparative studies with GaN evidenced the advantages of ZnO in terms of sensitivity of the strain-induced energy shift and of piezoelectric effect in heterostructures. © 2001 American Institute of Physics.

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