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A photoemission investigation into the reactivity of Au with ultrathin Si layers was undertaken.

YMnO3 thin films were grown on Si(111) using silicon oxynitride buffers.

GaAs surfaces were modified by undoped silicon and studied using x-ray photoelectron spectroscopy.

The viscosities of metaphosphate, pyrophosphate, molybdate and fluorophosphate glasses were measured in the shear deformation mode by applying the sandwich method from room temperature to the glass transition temperature Tg. Two relaxations were observed at lower and higher temperatures for glasses with long molecular chains, while only one relaxation was found at higher temperatures in glasses without the chain. A relationship between the frequency factor and the activation energy was observed for the high temperature relaxation.

High conversion efficiencies in ZnO n-Si junction solar cells are determined by preparing these cells by spray deposition of ZnO films on Si surfaces. The efficiencies range between 6.9 and 8.5%. The adjusting of deposition conditions results in the increase of the effective work function of ZnO films. This indicates that the high-energy barrier exists in the n-Si.

Spray pyrolysis method is used in the fabrication of indium-tin-oxide (ITO)/silicon oxide/mat-textured n-Si junction solar cells with an energy conversion efficiency of 15%. Junction solar cells which have an efficiency of 15% and a flat Si surface are used in the comparison of junction properties and characteristics. There is a very low open circuit photovoltage when the ITO film is deposited on a hydrofluoric acid-etched mat-textured Si surface. The occurrence of high density dislocations near the Si surface are indicated by scanning electron microscopy. The removal of interface states reduces the surface recombination current density.

The characteristics of electron-beam-evaporated indium tin oxide (ITO) thin films were investigated using x-ray photoelectron spectroscopy and work-function measurements. The results showed that all ITO films were comprised of crystalline and amorphous phases. The amount of the crystalline phase was not affected by post-deposition heat treatment. However, heat treatment increased the amount of the amorphous phase.

The characteristics of tin oxide films grown by electron beam evaporation were investigated. The resulsts showed that metal indium was not formed in the tin oxide films after deposition on an Si substrate at 200 degrees celsius due to increased surface diffusion of adsorbed species. The amount of metal indium significantly decreased when evaporation in oxygen gas was undertaken.

New technique of acoustic spectroscopy to study interface states in metal-oxide-semiconductor (MOS) structures with a very thin oxide layer based on the acoustoelectric effect resulting from the interaction between the longitudinal acoustic wave and semiconductor-insulator interface is presented. The essential principles and theoretical background of this acoustic spectroscopy technique that can determine the interface states distribution from the measured acoustoelectric response signal as a function of gate voltage (Uac-Ug characteristics) are described. The results obtained on the representative set of MOS structures prepared on both n- and p-type Si substrates by nitric acid oxidation of Si technology and undergone also some thermal treatment demonstrate that the introduced technique of acoustic spectroscopy can be a very useful tool for the interface states characterization. [ABSTRACT FROM AUTHOR]

We present that the tractional flow of a lubricant shows three kinds of limiting shear stresses at which the shear stresses take place independently of the shear rates in its viscous, viscoelastic, and glassy states. We propose three models on the mechanisms for the limiting shear stresses, based on the data of Brillouin spectra and viscosity of viscoelastic liquids previously reported by us and based on the data of the deformation of glassy polymers referred from others. The Brillouin spectra of a viscoelastic lubricant measured at up to 5 GPa at 25 and 80 °C show that we could not observe a frequency dispersion in sound waves below 0.8 GPa at 80 °C, while we can observe the frequency dispersion above 0.1 MPa at 25 °C owing to the viscosity of the lubricant. This result predicts the viscous limiting shear stress in the viscous state owing to the disappearance of meso-structures by heating and shearing under pressure. The viscosity of a polymer measured around the glass transition temperature (Tg) shows that Tg determined by the viscosity measurement is 27K lower than that determined by calorimetry. This result predicts the elastic limiting shear stress in the viscoelastic state near the glass transition pressure (Pg) owing to the shear thinning effect by shearing a lubricant film. In addition, there is the plastic limiting shear stress in the glassy state owing to the yield stress at which the tractional flow of a glassy lubricant behaves as a plastic solid. [ABSTRACT FROM AUTHOR]

Here we document the effect of flow configuration on the heat transfer performance of a serpentine shaped stream embedded in a conducting solid. Several configurations with fixed volume of fluid are considered: U-shaped with varying spacing between the parallel portions of the U, serpentine shapes with three elbows, and conducting soil with several parallelepipedal shapes. We show that the spacing must be greater than a critical value in order for the heat transfer density of the stream-solid configuration to be the highest that it can be. Spacings larger than this critical value do not yield improvements in heat transfer density. We also show that even though the heat transfer is time dependent, the stream-solid configuration has an effective number of heat transfer units Ntu that is nearly constant in time. The larger Ntu values correspond to the configurations with greater heat transfer density. [ABSTRACT FROM AUTHOR]

The GaAs surface with the native oxide formed by wet etching has been gradually deoxidized via evaporation of a silicon overlayer. Both chemical and electronic properties of such structures have been examined by x-ray photoelectron spectroscopy (XPS) and “XPS under biases,” respectively. The latter technique enables a direct assessment of the interface state density of insulator/semiconductor interfaces. We have concluded that gap states incident to the native oxide/GaAs interface have annihilated due to replacement of Ga–O bonds by Ga–Si and As–Si bonds. [ABSTRACT FROM AUTHOR]

We have grown YMnO[sub 3] (YMO) thin films on Si(111) using silicon oxynitride (SiON) as a buffer layer. Thickness of SiON buffer layer was well controlled within 2 nm. High resistance of ultrathin SiON layer (d[sub SiON]∼0.7 nm) to Si oxidation was confirmed by x-ray photoelectron spectroscopy (XPS). Using the ultrathin SiON layer, we obtained c-axis oriented ferroelectric phase of YMO. Although capacitance-voltage curves of Al/YMO/SiON/Si(111) showed hystereses attributed to ferroelectricity of the YMO films, the memory window was not sufficient (0.2 V), seemingly due to poor crystallinity of the YMO films. On the other hand, leakage current characteristic was good enough for application. The typical value of leakage current density was 10[sup -8] A/cm[sup 2] at a drive voltage of ±5 V. In this article, the details of the characterization elucidated by using x-ray diffraction, atomic force microscopy, and XPS will be shown as well. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

ZnS and ZnMgS layers have been grown onto GaP substrates by molecular beam epitaxy (MBE). The key parameters of the growth are a high substrate temperature and a high sulfur (S) beam pressure. The S beam pressure was typically 1×10[sup -2] Pa, which was more than one order of magnitude larger than in conventional MBE of ZnS. Using the high S beam pressure, large ZnS growth rate of 0.3–1.0 μm/h could be obtained even at 490 °C. The growth rate was limited by the Zn supply. Optimization of the S beam pressure reduces the full width at half maximum (FWHM) of the (400) double-crystal x-ray rocking curve (DCXRC). For a 2.1-μm-thick ZnS layer the width can be reduced to 400 arcsec. The low temperature photoluminescence (PL) spectra show sharp excitonic emissions including the free exciton emission. ZnMgS layers were grown onto ZnS buffer layers. The ZnMgS layers as well show good crystal and optical qualities. The FWHM of DCXRC of the 1.5-μm-thick Zn[sub 0.83]Mg[sub 0.17]S layer is 650 arcsec, which is comparable to the FWHM of a ZnS layer of similar thickness. The low temperature PL of the ZnMgS layer is dominated by a strong excitonic emission. The band gap of Zn[sub 1-x]Mg[sub x]S is estimated from reflection spectra. For x=0.20, the band gap is 3.974 eV. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Several studies are conducted to analyze the self heating property of the Ni[Fe.sub.2][O.sub.4] nanoparticles under the application of an ac magnetic field. The hysteresis loops obtained by the application of ac, as well as dc magnetic fields are also analyzed.

Presents a study that analyzed carrier transport mechanism of the silicon (Si) semiconductor solar cells with n-Si/indium tin oxide (ITO) junctions. Measurement of the current-voltage characteristics of the samples; Analysis of the conversion efficiency of the solar cells; Evaluation of the mechanism of charge transport of Si electrode covered with a thermally grown Si oxide layer where an ITO film is deposited.

Investigates the temperature dependence of nonlinear absorption in indium phosphide doping superlattices. Cause of the enhancement in nonlinearity; Coefficients of optical absorption; System to measure time response of nonlinear absorption.

Studies mechanism of carrier transport through a silicon-oxide layer for solar cells. Method of the study; Results and discussion;

Focuses on the fabrication of zinc oxide (ZnO) junction solar cells by a spray-pyrolysis method and high short-circuit photocurrent densities and relatively high photovoltages. Effect of the desorption of oxygen from the grain boundaries of the ZnO films; Measurement of current-voltage curves; Application of x-ray photoelectron spectra.

Examines domain structures and magnetic properties of domain refined grain-oriented silicon steel. Information on the domain refining effect caused by tensile stress; Details on domain refining due to flux emergence; Discussion on an approach to minimum loss in grain-oriented silicon steel.

The temperature rise of NiFe2O4 nanoparticles having diameters of 242 and 7.7 nm was measured. The results of the measurement were analyzed by comparing the areas of the hysteresis loops in order to clarify the mechanism of heat dissipation in the samples. The hysteresis loops were obtained by applying both ac and dc magnetic fields. It was found that the contribution of magnetic relaxation losses to the heat dissipation was negligible in the case of NiFe2O4 nanoparticle of diameter 242 nm. The contribution of the Néel relaxation to the heat dissipation in the case of NiFe2O4 nanoparticle of diameter 7.7 nm was observed as the difference between the areas of ac and dc hysteresis loops. From the dependences of temperature rise and hysteresis loops of the nanoparticles on the intensity and frequency of an applied magnetic field, the relaxation time for NiFe2O4 nanoparticle of diameter 7.7 nm was obtained as approximately 0.5-0.7 μs. [ABSTRACT FROM AUTHOR]

Emphasizes that bonding temperature and ferrite crystal orientation dominate pseudogap formation. Characteristics of the metal-in-gap (MIG) head; Influence of the annealing temperature on the diffusion at the boundary; Dependence of the ripple amplitude on the crystal orientation of ferrite cores.

Presents information on a study which synthesized nonthermodynamical garnet Bi[sub3]Fe[sub5]O[sub12] by direct epitaxial growth via vapor phase using a reactive ion beam sputtering technique. Use of the reactive ion-beam-sputtering method; Preparation of the bismuth-substituted iron garnet; Observation of the mazelike magnetic domains.

Focuses on a study that examined the dynamic domain wall movements in advanced grain-oriented silicon steel. Ways of decreasing iron losses; Methods of observing domain structures; Technique and instrument used to observe the domain wall movements.