bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Optical Constants of Thin Films from Measurements of Reflectance and Transmittance
Authors: Qingshan Bie Qingshan Bie , Byung-ki Cheong Byung-ki Cheong , Moonkyo Chung Moonkyo Chung , Zhensu Lin Zhensu Lin , Taek Sung Lee Taek Sung Lee , Won Mok Kim Won Mok Kim , Soon Gwang Kim Soon Gwang Kim
Published: October 2002

A new approach to determine the optical constants of thin films using a single wavelength light source without measurement of film thickness has been introduced in this paper. From the reflectance and transmittance measured over a range of film thicknesses, the optical constants of as-deposited GeSbTe alloy films at a wavelength of 685 nm as well as the film thickness at each point of measurement have been obtained by use of a nonlinear fitting. A self-consistent validation of the approach is also presented by comparing the optical constants obtained in both cases of film-incidence and substrate-incidence.
Enhanced Photovoltaic Response in Lead Lanthanum Zirconate-Titanate Ceramics with A-Site Deficient Composition for Photostrictor Application
Authors: Nonaka Kazuhiro , Akiyama Morito , Xu Chao-Nan , Hagio Tsuyoshi , Komatsu Masahiro , Takase Akira
Published: October 2002

Samples of (Pb0.97, La0.03)(Zr0.52, Ti0.48)1-0.03/4O3 (PLZT) ceramics with and without an A-site deficient composition of 1 mol% in ABO3 perovskite structures have been prepared by sintering at 1200°C for 2 h to investigate the photovoltaic response upon UV illumination, as well as the ferroelectric and piezoelectric parameters such as the polarization-electric field (P–E) hysteresis curve, strain constant, and dielectric constant. Results confirmed that the A-site deficient composition generates a photovoltaic current twofold higher than that in the sample without the deficient composition. In the ferroelectric and piezoelectric parameters, no significant difference was measured between the two samples. These results indicate that the photostrictor response is mostly determined by the photovoltaic properties and that the overall response speed of photostriction can be markedly improved by enhanced photovoltaic current.
Compositional Dependence of Hardness in ZnSe1-xTex and BeyZn1-ySe1-xTex
Authors: Maruyama Kenji , Suto Ken , Nishizawa Jun-ichi
Published: October 2002

Hardness characteristics were investigated on ZnSe1-x
Te
x
(0≤x≤0.06) and Be
y
Zn1-y
Se1-x
Te
x
(0≤x≤0.11, 0≤y≤0.10) bulk single crystals, which were grown by the vertical traveling solvent method using a tellurium solution. ZnSe-related mixed crystals containing tellurium and beryllium were harder than the binary ZnSe crystals due to their larger covalent binding energy. The values of the Vickers hardness showed 2.5 GPa for a ZnSe0.94Te0.06 crystal and 4.3 GPa for a Be0.10Zn0.90Se0.89Te0.11 crystal, compared to 1.1 GPa for a ZnSe crystal. The hardening effect by beryllium is estimated to be twice as effective as that by tellurium. The hardness of the mixed semiconductor crystals was expressed by the concentration of tellurium and beryllium to the 1/2 power. The 1/2 power law in mixed crystals should be clarified, considering the shear moduli related to the ionicity. The minimum etch pit density was 3.0×105/cm2 in a Be
y
Zn1-y
Se1-x
Te
x
crystal. This may be due to large compositional variations in the mixed crystals, which may influence the hardening effect.
Coating Shape Effect on Effective Conductivities of Aligned Long Elliptic Cylinder Reinforced Composites
Authors: Lu Shih-Yuan , Chen I-Cheng
Published: October 2002

The effect of coating shape on effective conductivities of aligned long elliptic cylinder reinforced composites is investigated for two types of coatings: uniform and confocal. The aligned elliptic cylinders are either randomly distributed or periodically arranged in space. It is found that uniform coating, under most circumstances, is more effective in enhancing or impairing the inclusion, while confocal coating performs better for enhancing parallel and impairing perpendicular components at thin coatings, and for impairing parallel and enhancing perpendicular components at thick coatings. The advantage of uniform coating over confocal coating becomes more pronounced with increasing inclusion aspect ratio. The regularity of array structure restricts the allowable coating ratio and gives rise to interesting behavior of the coating effect.
Orientation Control of Metalorganic Chemical Vapor Deposition-Bi4Ti3O12 Thin Film by Sequential Source Gas Supply Method
Authors: Watanabe Takayuki , Funakubo Hiroshi
Published: October 2002

C-axis-oriented Bi4Ti3O12 thin films were prepared on (111)Pt/Ti/SiO2/Si substrates by metalorganic chemical vapor deposition (MOCVD) using a sequential source gas supply method taking account of the crystal structure of Bi4Ti3O12 along the c-axis. The X-ray diffraction intensities of Bi4Ti3O12(006) and Bi4Ti3O12(117) increased and decreased, respectively, by the sequential source gas supply method and the conventional continuous source gas supply method. The sequential source gas supply method started from Bi double pulses as effective for the preparation of the c-axis-oriented Bi4Ti3O12 film, and the supply corresponding to a half unit cell per sequence showed high c-axis orientation.
Photoelectron Spectroscopy Study of the Oxidation of ZrC(100)
Authors: Kato Shin , Ozawa Ken-ichi , Edamoto Kazuyuki , Otani Shigeki
Published: October 2002

Ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) are used to study the oxidation of a ZrC(100) surface. When the surface is exposed to O2 at room temperature, carbon atoms in the surface region are found to be depleted and the substrate zirconium atoms are oxidized. The Zr oxide is proposed to be a ZrO-like state at low coverage (<3 L) and to become a ZrO
x
(1<x<2) state with further O2 exposure. When the 100-L-O2-exposed surface is heated at elevated temperatures, the work function is substantially decreased. By heating at 1000°C, the work function reaches a minimum value which is lower than that of the clean surface by 0.6 eV. The oxidation state which gives the minimum work function is deduced to be an ordered ZrO-like state whose periodicity is similar to that of ZrC(100) based on XPS and low-energy electron diffraction (LEED) measurements.
Visualizing the Interrelation between Surface Topograph and Surface Potential by means of a Scanning Maxwell Stress Microscope
Authors: Ozeki Kota , Itoh Junji , Yamamoto Shigehiko
Published: October 2002

An scanning Maxwell stress microscope (SMM) is utilized to visualize, on a microscale, the intercorrelation between the surface topograph and corresponding surface potential. It is found that the surface potential of the Fe–42Ni sample surface is weakly negatively correlated with the topographic height, while there is no correlation in the case of the Au surface used as a reference.
Dotted-Array Plasma Production by Using a Line-Focusing Lens System with Segmented Prism Array for Compact X-ray Laser Experiments
Authors: Yamaguchi Naohiro , Fujikawa Chiemi , Ohchi Tadayuki , Hara Tamio
Published: October 2002

A long narrow plasma originated from an array of microdots has been produced using a new line-focusing lens system. The lens system consists of a five-segmented prism array, a beam expander and a cylindrical lens assembly that was designed for compact X-ray laser experiments using a small Nd:YAG (yttrium aluminum garnet) laser. The irradiation pattern on a slab target has a small-scale intensity modulation due to interference among the segmented beams. The focused line has an array of microdots with a 50 µm diameter, a 140 µm spacing and an 11 mm length. Spectroscopic observation has been carried out in the expanding plasma produced by irradiating the YAG laser via this lens system onto an Al target. Near the target surface, highly ionized plasma was produced to have a spatial distribution corresponding to the microdot array in the irradiation pattern. It has been demonstrated that soft X-ray amplification takes place in the plasma produced by this irradiation method with very low input energy.
Electron Flow through Geometrical Discontinuity in Coaxial Magnetically Insulated Transmission Lines
Authors: Kazuki Hiraoka Kazuki Hiraoka , Mitsuo Nakajima Mitsuo Nakajima , Makoto Shiho Makoto Shiho , Kazuhiko Horioka Kazuhiko Horioka
Published: October 2002

Magnetically insulated transmission lines (MITLs) under high-power operation are dominated by space-charge current flowing between an anode and a cathode. When MITLs have geometrical discontinuity, the interaction between the disturbed electrons and the nonlinearly coupled electromagnetic field makes their behavior difficult to predict. The results of particle simulation show that the space-charge electrons tend to maintain the effective impedance of the transmission lines, by changing their distribution and the boundary of the electron cloud. Although a fraction of the space-charge flow shunts the gap at the discontinuity when the discontinuity is larger than a critical value, the total upstream current is still preserved. To discuss this impedance adjustment process and the critical value, we propose a laminar flow model with constant current density.
Microwave-Excited Large-Area Plasma Source Using a Slot Antenna
Authors: Kanoh Masaaki , Aoki Katsuaki , Yamauchi Takeshi , Kataoka Yoshinori
Published: October 2002

We developed a stable and uniform large-area plasma source using surface waves generated from a slot antenna. The propagation of microwaves radiating from the slot antenna was studied and the optimal shape of the slot antenna for uniform plasma generation was determined. The characteristics of a dry etching process using the plasma were also evaluated. It was confirmed that some of the microwaves which radiated from the slot antenna propagate as surface waves in the dielectric window. By adjusting the angle of the slot antenna, the plasma was generated in the direction perpendicular to the axis of the slot antenna. An Ar plasma electron density of the order of 1011/cm3, which exceeds the electron density required for blocking the propagation of microwaves (cutoff frequency), was obtained. On the basis of these observations, it was considered that the microwaves radiating from the slot antenna propagate in the form of surface waves in the direction perpendicular to the axis of the slot antenna, and generate surface-wave plasma. The results of the measurements of the etching rate and ashing rate yielded a poly-Si etching rate of 470 nm/min or greater with a uniformity of 5% or better, and an ashing rate of 3000 nm/min or greater with a uniformity of 7% or better. The poly-Si etching rate was approximately twofold and the ashing rate was approximately fivefold the corresponding values obtained by the conventional chemical dry etching method.
New Technique for Recording Enhanced X-Ray Fluorescence Hologram
Authors: Hayashi Kouichi
Published: October 2002

Weakness of the holographic undulation, which is about 0.3% in the angular distribution of the X-ray fluorescence intensity, has been a problem of X-ray fluorescence holography (XFH). In order to observe strong holographic undulation, I propose a new XFH technique which combines the normal XFH and inverse XFH, which are equivalent by virtue of the optical reciprocity theorem. This new technique is here termed “mixed XFH”. The performance of the mixed XFH was demonstrated by calculating the holographic intensities of Ge dimers and a Ge cluster. Amplitudes of the holographic undulations of the mixed XFH were twice as large as those of the conventional XFH. Furthermore, the image reconstructed from the theoretical mixed XFH data show atomic images as clear as those from the conventional XFH data.
Effect of Electron Beam on Velocities of Uranium Atomic Beams Produced by Electron Beam Heating
Authors: Ohba Hironori , Ogura Koichi , Nishimura Akihiko , Tamura Koji , Shibata Takemasa
Published: October 2002

Velocities of uranium atomic beams produced by two types of electron beams, a bent beam and a straight beam, were measured by a laser Doppler-shift technique. The atomic beams were accelerated to 1100 m/s and 900 m/s by free expansion near the evaporation surface with the bent beam and the straight beam, respectively. The higher velocity for the bent-beam evaporator was explained as follows. The evaporated atoms are excited or ionized more efficiently by the electron beam than for the straight-beam evaporator. The excitation and ionization energies contribute to the acceleration of the atomic beam. The attained velocities for the two types of electron beams were roughly estimated using the excitation and ionization energies derived from the electronic stopping power of uranium.
A Study of Ion Beam Etching of Polymethylmethacrylate Using N2 and N2/O2-Mixtures
Authors: Kozo Taguchi Kozo Taguchi , Tomohiko Ueguchi Tomohiko Ueguchi , Masahiro Ikeda Masahiro Ikeda
Published: October 2002

The influence of process parameters such as gas composition, kinetic energy of the ions and sample temperatures was studied in order to discuss the dry etching mechanism of polymers. First, we investigated polymer dry etching using N2 gas and verified that the heating temperature was the critical parameter in the case of polymer dry etching. Next, polymer dry etching was carried out using N2–O2 gas for obtaining smooth vertical side walls. The experimental results revealed that the generation of neutralized reactive species needed to be suppressed to form smooth vertical side walls.
Complex Spatiotemporal Dynamics of a 100-Emitter Laser Diode Array
Authors: Oishi Yuji , Nemoto Koshichi
Published: October 2002

Dynamics of large laser diode arrays (LD-arrays) consisting of many elements (emission regions) coupled to neighbor elements is of great interest, because chaotic oscillation has been reported even for 2-emitter LD-arrays. The main objective of this study is to investigate the complex spatiotemporal dynamics of a LD-array consisting of 100 emitters using the evanescent coupling mode model. As the coupling strength is increased, the LD-array goes from (i) a homogeneous steady state to (ii) a period T state in which all sites have equal temporal period, to (iii) a spatially-varying temporal period state, and finally to (iv) spatiotemporal chaos. In state (ii), the spatially and temporally ordered pattern which consists of two subsets (odd- and even-numbered sites) is self-generated from a random initial condition. In state (iii), ordered and chaotic sites can coexist in the same system. This characteristic is due to the mutual interaction of many elements, and does not appear in the case of a 2-emitter array.
Characterisation of Microstructure of Isothermally Transformed Martensite in Low Temperature in Powder and Bulk State of Fe–23Ni–3.6Mn (mass%) Alloy by Rietveld's Method
Authors: Chanda Arunima , De Madhusudan , Kajiwara Setsuo
Published: October 2002

The present study concerns X-ray characterisation of the
microstructures of the martensites of Fe–23Ni–3.6Mn alloy, transformed
isothermally at low temperature. Along with the austenized powder and
bulk forms of the alloy, coldworked powders have also been
analysed. The methodology adopted is Rietveld's whole profile fitting
technique which incorporates correction for preferred orientation of
the crystallites. The results reveal important information on the
crystallite (domain) sizes, residual microstrains, preferred
orientation, stacking and compound fault probabilities, dislocation
density etc., for both the austenite and martensite phases of the
alloy. The martensite has smaller crystallite sizes and larger
microstrain values, both of which are isotropic in nature for the
transformed bulk and the austenized powders but anisotropic for the
coldworked powders. The transformed matrix revealed high percentage of
martensites in coldworked powder and bulk whereas annealed powder
revealed about 8% volume fraction of martensites. The dislocation
density values evaluated from the respective
crystallite sizes and r.m.s. strain values are high
(∼1011 cm/cm3) in the martensitic phase by almost an
order of magnitude compared to their respective
austenite phase. The coldworked powder reveals high
propensity of faulting. The hardness value of
transformed bulk (191 kg/mm2) is more than double
the value for the austenite bulk (95 kg/mm2). The
results have been compared and correlated with those
in two previous studies on the same alloy system
having 3.3 and 3.8 mass% of Mn.
Preparation and Characterization of Ferroelectric BaTi0.91(Hf0.5, Zr0.5)0.09O3 Thin Films by Sol-Gel Process Using Titanium and Zirconium Alkoxides
Authors: Thongrueng Jirawat , Nishio Keishi , Nagata Kunihiro , Tsuchiya Toshio
Published: October 2002

Sol-gel-derived BaTi0.91(Hf0.5, Zr0.5)0.09O3 (BTHZ-9) thin films have been successfully prepared on Pt and Pt(111)/Ti/SiO2/Si(100) substrates by spin-coating and sintering from 550 to 900°C for 2 h in oxygen ambient. X-ray diffraction measurement indicated that the single perovskite phase of the BTHZ-9 thin films was obtained at heat treatment above 650°C. The formation temperature of the double-alkoxy-derived BTHZ-9 thin films was lower by at least 80°C than that of the films prepared from only titanium alkoxide. The microstructure of the films was observed by atomic force microscopy and scanning electron microscopy. The grain size of the films increased from 70 to 200 nm with increasing sintering temperature ranging from 650 to 850°C. The maximum peak for the dielectric constant, corresponding to the Curie point (87°C), was broad and lower in magnitude compared with that of the BTHZ-9 bulk ceramics. Tensile stresses resulting from the differences between thermal expansion coefficients of the substrate and the film caused poor electrical properties. BTHZ-9 thin films exhibited a well-saturated polarization-electric field hysteresis loop. The polarization and coercive field for the 850-nm-thick BTHZ-9 thin film prepared on Pt/Ti/SiO2/Si substrate at 750°C were determined to be 8 µC/cm2 and 15 kV/cm, respectively. Those of the BTHZ-9 thin film prepared on Pt substrate at 850°C were found to be 9 µC/cm2 and 18 kV/cm, respectively.
Measurement of Electric-Field-Induced Displacements in (Pb, La)TiO3 Thin Films Using Scanning Probe Microscopy
Authors: Maiwa Hiroshi , Ichinose Noboru
Published: October 2002

Electric-field-induced displacements in sputter-deposited (Pb, La)TiO3 thin films were investigated. Dynamic displacement-voltage hysteresis loops were measured by scanning probe microscopy. A strain of 0.08 to 0.1% was observed using a bipolar driving field of 142 kV/cm. Using a phenomenological approach, the field-induced piezoelectric and electrostrictive displacements were estimated from measured polarization and field-dependent permittivity data. Qualitative agreement was observed between the measured and calculated displacements. The compositional dependence of thin films was analyzed from the ratio of piezoelectric and electrostrictive displacements.
Crystallization of Sr0.5Ba0.5Nb2O6 Thin Films on LaNiO3 Electrodes by RF Magnetron Reactive Sputtering
Authors: Jong Chao-An , Gan Jon-Yiew
Published: October 2002

Strontium barium niobium (Sr0.5Ba0.5Nb2O6)
(SBN) thin films are
prepared on conductive-oxide LNO (LaNiO3) electrodes by the rf
magnetron sputtering system. Instead of conventional furnace
annealing, SBN thin films are crystallized by rapid thermal annealing
(RTA) above 700°C for 5 min. The textured SBN films are crystallized
with two orientations: one is the (001) or (310) direction, and the
other is the (002) or (620) direction. Films compositions measured by
the electron spectroscopy of chemical analysis (ESCA) quantitative
analysis method show nearly the same stoichiometric ratio as the
target. The depth profiles of SBN films and the target are examined by
secondary ion mass spectrometer (SIMS). The concentrations of the
films are quite uniform. After being heat treated at 800°C for 5 min
by RTA, La and Ni diffuse into the SBN film. The diffusion coefficient
of La in SBN films is also calculated.
Effects of Pt/SrRuO3 Top Electrodes on Ferroelectric Properties of Epitaxial (Pb, La)(Zr, Ti)O3 Thin Films
Authors: Kobune Masafumi , Matsuura Osamu , Matsuzaki Tomoaki , Mineshige Atsushi , Fujii Satoshi , Fujisawa Hironori , Shimizu Masaru , Niu Hirohiko
Published: October 2002

Epitaxially c-axis oriented PLZT films with the composition (Pb0.925La0.075)(Zr0.4Ti0.6)O3 were deposited on Pt/MgO(100) substrate by rf-magnetron sputtering using a compacted powder target with the composition (0.8PLZT+0.2PbO). Pt/SrRuO3(SRO)/PLZT/Pt capacitors were successfully fabricated by forming Pt/SRO top electrodes onto PLZT films. The 206-nm-thick PLZT films with layered Pt/SRO top electrodes exhibited a slightly high leakage current at a low electric field, compared with PLZT films with the same thickness and a single Pt top electrode. The values of switchable polarization after 1010 cycles for Pt/PLZT/Pt capacitors decreased up to around 17% of their initial values, whereas the switchable polarization for Pt/SRO/PLZT/Pt capacitors hardly exhibited any fatigue degradation due to polarization reversal. The layered Pt/SRO is useful as a top-electrode material for fabricating the low leakage and high endurance ferroelectric capacitors.
Microstructure and Absorption Property of Silver-Black Coatings
Authors: Wang Chih-Ming , Chen Ying-Chung , Lee Maw-Shung , Chen Kun-Jer
Published: October 2002

Silver black was deposited on SiO2/Si substrates by thermal
evaporation under various gas atmospheres (Ar and N2). The
dependence of surface morphology evolution of silver-black coating on
deposition parameters was studied. The metal-black layers obtained by
evaporation are reproducible. With an increase of deposition pressure,
the amount of porosity increases but the grain size and the electrical
conductivity of the porous film decrease. The microstructure of the
silver black deposited under Ar gas is more porous than that deposited
under N2 gas using the same deposition process. In addition, the
infrared (IR) absorption of the silver-black layer increases as the
deposition pressure increases. In comparison with gold-black coatings,
the IR absorption of silver black is clearly better. The silver-black
coating deposited under an argon atmosphere exhibits an excellent
absorption (96%) at the deposition pressure of 750 mTorr.
Preparation and Properties of Bi2SiO5/Si Structures
Authors: Masaki Yamaguchi Masaki Yamaguchi , Kouji Hiraki Kouji Hiraki , Takao Nagatomo Takao Nagatomo , Yoichiro Masuda Yoichiro Masuda
Published: October 2002

Bismuth silicate (Bi2SiO5) films, expected as the intermediate buffer layer between the bismuth layer-structured ferroelectrics (BLSF) and silicon substrate, were prepared on (100)-oriented silicon wafers by rf magnetron sputtering. The c-axis-oriented Bi2SiO5 films with smooth surface morphology were obtained at the substrate temperature of 400°C. The leakage current density is on the order of 10-10 A·cm-2, under the applied electric field of less than 350 kV·cm-1. From capacitance–voltage characteristics measurement results, it is worth noting that hysteresis is hardly observed. The interface trap density at the midgap is estimated to be approximately 6 ×1012 cm-2·eV-1. The numerical evaluation results indicate that the metal-ferroelectric-insulator-semiconductor (MFIS) capacitor can be reversed at a low applied voltage. This suggests that Bi4Ti3O12/Bi2SiO5/Si structures are suitable for application for ferroelectric memory devices.
Study of Occupational Sites and Dielectric Properties of Ho–Mg and Ho–Mn Substituted BaTiO3
Authors: Kishi Hiroshi , Kohzu Noriyuki , Iguchi Yoshiaki , Sugino Junichi , Kato Makoto , Ohsato Hitoshi , Okuda Takashi
Published: October 2002

The effect of re-oxidation treatment on the solubility in dopants and the dielectric properties of Ho–Mg- and Ho–Mn-substituted BaTiO3 was investigated. The lattice parameter and electrical resistivity results indicated that the predominant occupational sites of Ho ions changed from A-sites to B-sites by increasing the doped content in both systems. In the case of Ho–Mn-substituted samples, the decrease in lattice parameter and a shift of the Curie point (T

c
) to higher temperatures by re-oxidation treatment were observed in the range in which Ho ions predominantly occupy B-sites (act as acceptors). On the other hand, Ho–Mg-substituted samples showed little change. Electron spin resonance measurements revealed that these changes due to re-oxidation were based on the decrease of the ionic size of Mn due to the oxidation of Mn2+ to Mn3+ or Mn4+. The occupational sites of Ho ions strongly affected the valence state of Mn and the dielectric properties of BaTiO3.
Structure Identification and Electrical Properties of the New Pyrochlore Phase in the Sr–Bi–Ta–Ti–O System
Authors: Lu Chung-Hsin , Fang Bu-Kuan , Wen Cheng-Yen
Published: October 2002

A new pyrochlore phase Sr0.5BiTaTiO6.5 has been successfully synthesized via a solid state reaction, and its crystal structure and electrical properties are also investigated in this study. When the amount of TiO2 added in the starting materials is insufficient, a secondary phase-SrBi2Ta2O9 is formed with the pyrochlore phase; however, when an ample amount of TiO2 is added, some excess TiO2 remains in the bulk. The structure refinement based on the Rietveld method corroborates the finding that Sr0.5BiTaTiO6.5 exhibits a cubic Fd3m structure with a lattice constant a
0=10.424 Å, and the theoretical density is calculated to be 6.867 g/cm3. The exact position of each atom in Sr0.5BiTaTiO6.5 is determined, and the ideal crystal structure model is constructed. According to the dielectric measurement and polarization analysis, it is found that the densified Sr0.5BiTaTiO6.5 exhibits paraelectric characteristics at room temperature with a low dielectric constant (94.8 at 10 kHz). In addition, the dielectric constant of this pyrochlore phase shows a rather weak dependence upon temperature as well as frequency.
Actuation Properties of Lead Zirconate Titanate Thick Films Structured on Si Membrane by the Aerosol Deposition Method
Authors: Lebedev Maxim , Akedo Jun , Akiyama Yoshikazu
Published: October 2002

The results of the direct deposition of lead zirconate titanate [Pb(Zr0.52, Ti0.48)O3] (PZT) thick film on a Si-based structure are presented. The construction of a bottom electrode is very important for successful deposition. The actuation properties of PZT on the Si membrane were investigated. For a 6.2×6.1 mm2, 65-µm-thick Si membrane driven by a 4.7×4.3 mm2, 13-µm-thick PZT layer, the deflections, which were 1.5 µm upon applying 52 V at nonresonance frequency and 22 µm upon applying 8 V at resonance frequency, were measured.
An Analysis of Jumping and Dropping Phenomena of Piezoelectric Transducers using the Electrical Equivalent Circuit Constants at High Vibration Amplitude Levels
Authors: Umeda Mikio , Nakamura Kentaro , Takahashi Sadayuki , Ueha Sadayuki
Published: October 2002

This paper presents an analysis of the jumping and dropping phenomena of piezoelectric transducers, using the electrical equivalent circuit constants at high vibration amplitude levels of resonance based on the electrical transient response technique. The calculated frequency characteristics well simulated the measured ones driven by a constant voltage source. It is clarified from the results that the jumping and dropping phenomena are caused mainly by the nonlinear behavior of the elastic constant at high vibration amplitude levels. The effects of the loss, the voltage and the driving method are also discussed.
A New Nondestructive Evaluation Method for Surface Acoustic Wave Velocity
Authors: Jian Chunyun , Tsuboi Atsushi , Uda Satoshi
Published: October 2002

A new nondestructive evaluation method for surface acoustic wave (SAW) velocity on a piezoelectric wafer was proposed. Split electrodes were formed on a glass wafer and a nonconductive liquid was interposed between the piezoelectric wafer and the glass wafer. The mode of the SAW excited on the piezoelectric wafer surface was leaky (LSAW) and its velocity was evaluated using the electrical reflection characteristics of the split electrodes. The usefulness of the new method was experimentally proven by showing the high reproducibility of the measured velocity and the agreement between the measured and calculated values indicating the SAW characteristics on a rotated-Y langasite wafer.
Viscosity Measurement of Ferroelectric Liquid Crystal Using Shear Horizontal Wave Propagation in a Trilayer Structure
Authors: Masaru Inoue Masaru Inoue , Hiroshi Moritake Hiroshi Moritake , Kohji Toda Kohji Toda , Katsumi Yoshino Katsumi Yoshino
Published: October 2002

Propagation characteristics of a shear horizontal (SH) wave in a trilayer structure, having a viscous liquid layer between a piezoelectric ceramic plate and a glass plate, are described on the basis of numerical and experimental investigations. Viscosity dependences of mechanical displacement distributions and relationships between the fractional velocity change and the square root of viscosity are discussed. The viscosity is related to the acoustic phase delay, accompanied by the SH wave propagation, between two interdigital transducers on the SH wave device. The measured temperature dependence of viscosity of silicon oil is in good agreement with the numerical analysis result of the SH wave propagation. An electrorheology effect and the temperature dependence of the viscosity in a ferroelectric liquid crystal (FLC: CS1014) are also measured by this technique.
Terahertz Response of Bulk Ba(Mg1/3Ta2/3)O3
Authors: Tsai Tsong-Ru , Liang Mei-Hui , Hu Chen-Ti , Chi Cheng-Chung , Lin I-Nan
Published: October 2002

We have measured the complex index of refraction of Ba(Mg1/3Ta2/3)O3 bulk material using coherent THz time domain spectroscopy. The transmission spectrum of Ba(Mg1/3Ta2/3) in the 0.1–1.0 THz region is obtained. The real part of the index of refraction of Ba(Mg1/3Ta2/3) in this band is estimated (∼4.87), and is comparable with the dielectric constant measured at microwave frequency. The measured Q-factor is around Q·f=40 THz, which is slightly smaller than the Q·f-values of the Ba(Mg1/3Ta2/3)O3 materials in the microwave regime (Q·f=60,000 GHz in 10 GHz).
Dielectric and Piezoelectric Properties of 0.91Pb(Zn1/3Nb2/3)O3–0.09PbTiO3/ Polyvinylidene Fluoride Composites Produced by the Sol-Gel Method
Authors: Tajitsu Yoshiro , Yonezawa Masato , Sato Akira , Tomiyama Hiroyuki , Date Munehiro , Fukada Eiichi , Yamashita Yohachi
Published: October 2002

In order to investigate the piezoelectric properties of composite films of 0.91Pb(Zn1/3Nb2/3)O3–0.09PbTiO3 (PZNT) and polyvinylidene fluoride (PVDF) prepared by the sol-gel method in comparison with those of PVDF, copolymers of vinylidene fluoride and trifluoroethylene (P(VDF/TrFE)), and polyurea-5, the residual polarization P
r and the electromechanical coupling factor k
33 were measured. The results verified that PZNT- and PVDF-composite-film (PZNT/PVDF film) manufacturing method can effectively realize a uniformly large area composite membrane. We obtained the apparent P
r of PZNT/PVDF film in D-E hysteresis measurements. The k
33 value of the PZNT/PVDF film is about 0.08. The k
33 value is approximately 1/4 that of the β-PVDF or P(VDF/TrFE) film.
Particle-Size Dependence of Crystal Structure of BaTiO3 Powder
Authors: Yamamoto Takashi , Niori Hirotake , Moriwake Hiroki
Published: October 2002

The particle size dependence of BaTiO3 powder was investigated from the viewpoint of the crystal phase. The crystal phase of BaTiO3 powder was transformed from tetragonal to cubic at a critical particle size of 0.1 µm at room temperature. With decreasing particle size, the Ba ions in the BaTiO3 structure were absent at the surface, and these disordered surface areas increased in small-particle-size BaTiO3 powders and exhibited particle-size dependence.
Theoretical and Experimental Study on Nanoscale Ferroelectric Domain Measurement Using Scanning Nonlinear Dielectric Microscopy
Authors: Hiroyuki Odagawa Hiroyuki Odagawa , Yasuo Cho Yasuo Cho
Published: October 2002

We describe theoretical and experimental studies for nano-scale ferroelectric domain measurements using scanning nonlinear dielectric microscopy (SNDM). We calculate one-dimensional images of a 180° c-c domain boundary and show that SNDM has an atomic-scale resolution theoretically. Experimental results show that we measure the c-c domain on the lead zirconate titanate (PZT) thin film with the width of 1.5 nm and that the resolution of the microscope is less than 0.5 nm.
Scanning Rapid Thermal Annealing Process for Poly Silicon Thin Film Transistor
Authors: Kim Tae-Kyung , Kim Gi-Bum , Yoon Yeo-Geon , Kim Chang-Hoon , Lee Byung-Il , Joo Seung-Ki
Published: October 2002

Polycrystalline silicon (poly-Si) thin-film transistors (TFTs) were fabricated on transparent glass substrates using lamp-scan rapid thermal annealing. Scan-radiation-annealed silicon islands were crystallized by metal-induced lateral crystallization (MILC). The activation energy of Ni-MILC was calculated to be 1.56 eV. In order to enhance the MILC rate, we deposited a capping SiO2 layer over the self-aligned TFT, which was found to increase the MILC rate several times. Thus fabricated TFTs exhibited different electrical characteristics depending on the annealing conditions.
Characteristics of Intensity Noise Reduction of Optical Pulses Using Variable Spectral Filters and Optical Fibers
Authors: Nishizawa Norihiko , Higuchi Junichi , Mori Masakazu , Yamane Kazuo , Goto Toshio
Published: October 2002

Noise reduction of optical pulses using variable spectral filters and optical fibers in the anomalous dispersion region is investigated numerically and experimentally. In the numerical analysis, quantum noise evolution of the optical pulse is calculated using a quantized nonlinear Schrödinger equation and linearization approximation. It is shown that when the optical spectrum is in the broadening process, photon-number squeezing can be obtained using a band-pass filter. On the other hand, when the optical spectrum is in the narrowing process, a correlated pulse pair is generated using a band-rejection filter and photon number squeezing can be also observed. In the experiment, the characteristics of noise reduction of optical pulses are investigated using a passively mode-locked fiber laser at 1.55 µm and a variable spectral filter. Noise distribution of optical pulses changes periodically as the fiber input power is changed. Intensity noise of the fiber laser is reduced by as much as 23 dB using the band-pass filter and is slightly reduced below the shot noise level. Using the band-rejection filter, the noise reduction by the correlated pulse pair is confirmed. The characteristics of the experimental results are almost in agreement with those of the numerical ones.
Theoretical Analysis of GaInAsP/InP Multiple Micro-Cavity Laser
Authors: Raj Mothi Madhan , Serizawa Naoki , Wiedmann Jörg , Arai Shigehisa
Published: October 2002

Fundamental lasing properties of a new type of laser, which consists of a multiple micro-cavity structure with vertical grooves, was theoretically investigated based on an improved perturbation feedback theory in combination with the transfer matrix method. In order to suppress a diffraction loss between semiconductor micro-cavities, an MMC laser having grooves buried with low loss polymer (Benzocyclobutene: BCB) was proposed. Attainable maximum reflectivity was calculated to be higher than 98% for quarter wavelength wide grooves buried with BCB polymer (refractive index of 1.546, number of the micro-cavity elements of 8), which was higher than that of the semiconductor micro-cavity/air groove periodic structure. As a result, a moderately low threshold current operation (1 mA for a stripe width of 1 µm) can be obtained for the total cavity length of 45 µm with the micro-cavity length of 4.90 µm (9 elements).
A Two-Dimensional Simulation of Pulsed Discharge for a Color DC-Type Plasma Display Panel
Authors: Yukio Murakami Yukio Murakami , Hideomi Matsuzaki Hideomi Matsuzaki , Hiroshi Murakami Hiroshi Murakami , Kunihide Tachibana Kunihide Tachibana
Published: October 2002

Two-dimensional spatio-temporal behaviors of particle densities were investigated in a pulsed microdischarge cell of a DC-type plasma display panel (PDP) filled with a mixture of He and Xe gases. In the computer simulation, a fluid model was employed under local field approximation (LFA) for electrons, four kinds of ions, and seven kinds of excited species. Twelve simultaneous continuity equations were solved together with Poisson's equation with consideration of the absorption and reemission of imprisoned resonant radiations, and also the secondary electron emission at the cathode due to incidences of ions, metastable atoms and vacuum ultraviolet (VUV) photons. The results on the density of the resonance state Xe*(1s
4) atoms, metastable state Xe*(1s
5) atoms as well as the discharge current waveform, showed good agreement with the corresponding experimental results. The effects of electrode size and gap length were also investigated.
Growth of Ga0.46In0.54NyAs1-y Single Quantum Wells on InP(100) Substrate by Metalorganic Chemical Vapor Deposition
Authors: Ubukata Akinori , Dong Jie , Matsumoto Koh , Ishihara Yoshio
Published: October 2002

GaInNAs has been demonstrated as a 1 eV material that is lattice-matched to GaAs. Similarly, it is expected that for GaInNAs, which is lattice-matched to InP with an In content of over 50%, a band gap from 0.7 to 0.3 eV should be achievable if a few percent N could be incorporated. A Ga0.46In0.54N
y
As1-y
/InP single quantum well (SQW) structure grown at a relatively high growth temperature has been attempted. Low AsH3 partial pressure appeared to enhance N incorporation. A strong photoluminescence (PL) emission was observed without post-growth annealing at the growth temperature of 650 to 680°C. For our reactor, the PL properties of GaInNAs appeared to improve for the growth pressure of 120 Torr since a narrow PL linewidth as low as 32 meV was obtained at that pressure. In the low-temperature PL measurement, blue shift was observed.
Measurement of Stress near Dislocation Walls in a ZnSe Signal Crystal by Raman Scattering Tomography
Authors: Tsuru Toshihide , Sakai Kazufumi , Ma Minya , Ogawa Tomoya
Published: October 2002

Intensity and wavenumber of the transverse optical (TO) and longitudial optical (LO) modes of Raman peaks were respectively measured as a function of distance from a dislocation wall in a ZnSe single crystal grown by vapor phase method. The peak intensity of the LO mode was increased but that of the TO mode was decreased with distance from the wall, while wavenumber of the LO mode peak was clearly decreased with distance. According to the scattered light intensity against polarization configuration, it is concluded that there is no twinning across the wall. Wavenumber of the LO mode peak was qualitatively measured as a function of distance from the wall center, and a compressive stress in the matrix was introduced along the wall. This stress was numerically estimated as 1×108N/m2in the dislocation wall.
Sequential Single-Oriented Growth of (111) Cu/(111) HfN/(002) Hf Trilayered Film on (001) Si and Its Thermal Stability
Authors: Satoko Shinkai Satoko Shinkai , Ken-ichi Yoshimoto Ken-ichi Yoshimoto , Yasuhiro Kitada Yasuhiro Kitada , Katsutaka Sasaki Katsutaka Sasaki
Published: October 2002

We investigated the sequential single-oriented growth of Cu/HfN/Hf trilayered film on Si and the interfacial solid-phase reaction of the Cu/HfN/Hf/Si contact system by X-ray diffraction, Auger electron spectroscopy and X-ray photoelectron spectroscopy analyses. Sequential single-oriented growth of (111) Cu/(111) HfN/(002) Hf trilayered film was realized on (001) Si when a HfN (300 Å)/Hf (300 Å) bilayered film was interposed between Cu and Si. It was revealed that this contact system can tolerate temperatures of up to 520°C, which is much higher than the temperature (400°C) required for the conventional post-metallization process, maintaining a Hf3Si2 silicide adhesion layer with the lowest contact resistivity at the Si interface and a (111) Cu overlayer with excellent electromigration resistance.
Thermochromic VO2 Films Deposited by RF Magnetron Sputtering Using V2O3 or V2O5 Targets
Authors: Shigesato Yuzo , Enomoto Mikiko , Odaka Hidehumi
Published: October 2002

Thermochromic monoclinic-tetragonal VO2 films were successfully deposited on glass substrates with high reproducibility by rf magnetron sputtering using V2O3 or V2O5 targets. In the case of reactive sputtering using a V-metal target, the VO2 films could be obtained only under the very narrow deposition conditions of the “transition region” where the deposition rate decreases drastically with increasing oxygen gas flow rate. In the case of a V2O3 target, polycrystalline VO2 films with a thickness of 400 to 500 nm were obtained by the introduction of oxygen gas [O2/(Ar+O2)=1–1.5%], whereas hydrogen gas [H2/(Ar+H2)=2.5–10%] was introduced in the case of a V2O5 target. Furthermore, the VO2 films were successfully grown heteroepitaxially on a single-crystal sapphire [α-Al2O3(001)] substrate, where the epitaxial relationship was confirmed to be VO2(010)[100]∥Al2O3(001)[100], [010], [110] by an X-ray diffraction pole figure measurement. The resistivity ratio between semiconductor and metal phases for the heteroepitaxial VO2 films was much larger than the ratio of the polycrystalline films on glass substrates under the same deposition conditions.
Effect of an Atomic Scale Protrusion on a Tip Surface on Molecular Stick-Slip Motion and Friction Anisotropy in Friction Force Microscopy
Authors: Ohzono Takuya , Fujihira Masamichi
Published: October 2002

A molecular dynamics (MD) method is used to simulate the molecular stick-slip motion and the friction anisotropy observed experimentally between an atomic force microscope (AFM) tip and an ordered monolayer of n-alkane chains which tilt in one of six equivalent stable directions. A slider with a single atomic scale protrusion, connected to an external force control unit via three orthogonal springs, is used to model the AFM tip apex with cantilever springs under feedback regulation of the applied normal force. Although there is almost no interfacial commensurability between the tip atomic lattice and the sample molecular lattice, molecular lattice-resolved images are observed due to molecular scale stick-slip motion when the size of the protrusion is comparable to the molecular lattice constant. The present MD simulation can provide an explanation of why we can see a molecular lattice in contact AFM.
Unstable Behavior in Exploding Wire Array
Authors: Shimomura Naoyuki , Nagata Masayoshi , Teramoto Yusuke , Akiyama Hidenori
Published: October 2002

Although considerable investigations have been reported on z-pinches to achieve nuclear fusion, little attention has been given from the point of view of how a wire array consisting of many parallel wires explodes. In this paper, the unstable behavior of a wire array is investigated. The instability occurs by the deviation from the homogeneous current flow through many wires. The expressions discriminating between the stability and the instability are derived. Using the resistivity variation of the wire, the unstable behavior during the explosion of the wires is predicted and the strength of the tendency to an unstable behavior is evaluated. The unstable region on a map of resistivities is independent of the wire number while the strength of the tendency to the unstable behavior depends on the wire number.
Characterization of an Imaging Extreme-Ultraviolet Flat-Field Spectrometer and Its Application to Extreme-Ultraviolet Emission Profile Measurement
Authors: Kim Jaehoon , Kim Dong-Eon
Published: October 2002

The spatial imaging property of an extreme-ultraviolet (XUV) flat-field spectrometer was studied using ray-tracing and measured experimentally. Under the condition that the spectrometer is stigmatic at 10 nm, ray-tracing simulations show that the spatial resolution is expected to be about 18 µm in the wavelength range from 2.5 nm to 30 nm. The measurement of the spatial resolution, using a wire as fiducial 20 mm away from the source position along the optical axis, was carried out for the CV resonance line (4.03 nm) and a spatial resolution of 70 µm was obtained. This value agrees well with the ray-tracing result for a source displaced 20 mm along the optical axis. Using the spatial imaging property of this spectrometer, the emission profiles of CV 1s
2–1s3p (3.50 nm) and CVI L
β (2.85 nm) lines from a laser-produced carbon plasma were measured. The spatial imaging property and Abel inversion were applied to laser-produced carbon plasma spectra to deduce emission profiles.
Determining Flexural Rigidity Distribution of a Composite Bending Beam
Authors: Wang Ning , Yu Chengjian
Published: October 2002

In this paper, we develop a technique in which the flexural rigidity distribution of a composite bending beam can be approximately determined by minimizing the error between the measured and simulated data excited by a point source. A practical example shows the technique to be effective.
Gauge Block Measurement Using a Wavelength Scanning Interferometer
Authors: Bitou Youichi , Seta Katuo
Published: October 2002

A gauge block measurement system that uses a wavelength scanning interferometer was developed. By using a wavelength scanning technique, we determined the integer part of the interference fringe order. From that integer part, we determined the absolute length of a gauge block using only a single light source (wavelength scanning laser diode), even when no information on the nominal length of the gauge block was available. Using the Fourier transform technique to analyze the interference fringe, we measured the excess fraction parts of the interference fringe order with a resolution of over 0.003, and then we determined the integer part of the fringe order in the test measurement of a 10 mm gauge block. It was estimated that we could determine the integer part when the nominal length was shorter than approximately 100 mm, which can be expanded by improving the frequency stability of the light source. The final uncertainty was similar to that obtained with a conventional system based on a multiple wavelength interferometer.
Site-Specific Studies on X-Ray Magnetic Circular Dichroism at Fe K Edge for Transition-Metal Ferrites
Authors: Matsumoto Kenji , Saito Fumikazu , Toyoda Takeshi , Ohkubo Koichi , Yamawaki Koji , Mori Takeharu , Hirano Keiichi , Tanaka Masahiko , Sasaki Satoshi
Published: October 2002

Experiments on X-ray magnetic circular dichroism (XMCD) were performed with synchrotron radiation for Zn and Mn–Zn ferrites (normal-spinel structure) and Ni, Co and Cu ferrites and magnetite (inverse-spinel structure). The inverse-spinel ferrites have positive-to-negative dispersion-type XMCD signals in the pre-edge region of the Fe K edge, which originate from Fe3+ ions in the A sites. There are no such signals for normal-spinel ferrites. Two kinds of negative-to-positive dispersion-type XMCD signals were observed in 7.119–7.125 keV and 7.122–7.129 keV regions of the main edge, which are caused by a mixture of Fe3+ and Fe2+ ions of the B sites in magnetite and Fe3+ ions of the B sites in the other inverse-spinel ferrites, respectively. The B-site origin of the XMCD main-edge spectra was also confirmed by observation of X-ray resonant magnetic scattering for the 222 reflection of Ni ferrite.