bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical Analysis on Phototaxis of Goldfish in an Experimental Vessel
Authors: Sato Tadashi , Terao Kunio
Published: November 2005

Phototactic responses of a goldfish in a vessel are discussed according to the experimental results by an optical apparatus connected to a microcomputer. Assuming that the fish performs the lactic response not only to the incident light but the wall of the vessel, one can determine the one-dimensional position distribution of the fish in the light beam as a steady state solution of the telegraph equation with a drift term. It is found that the fish is uniformly attracted to the light source all over the vessel, but attracted to the wall only within a certain distance.
Control of ZnSe Film Stoichiometry at ZnSe/GaAs Interface Grown by MOCVD
Authors: Suemune Ikuo , Ohmi Koutoku , Kanda Takashi , Yukutake Kazutoshi , Kan Yasuo , Yamanishi Masamichi
Published: November 2005

ZnSe film stoichiometry at a ZnSe/GaAs interface was found to be critically dependent on the surface conditions of the GaAs substrate. It is shown for the first time that the main factor governing the interface stoichiometry is the competition between the Zn–As bondings and the Ga–Se bondings at the interface.
Evidence for Creation of Gallium Antisite Defect in Surface Region of Bleat-Treated GaAs
Authors: Hiramoto Toshiro , Mochizuki Yasunori , Ikoma Toshiaki
Published: November 2005

The origin of a defect responsible for a 1.44 eV photoluminescence band in Si implanted GaAs, which is created during annealing at high temperatures and affects the activation efficiency, was investigated. An identical 1.44 eV PL band is observed even in unimplanted LEC, LPE and HB GaAs, indicating that Si and B atoms are not involved in the defect. We observed for the first time 1.32 and 1.28 eV PL bands in Si-implanted and annealed LEC GaAs. These are considered to be related to a negative charge state of a 77 meV double acceptor. It is concluded from these results that the defect giving rise to the 1.44 eV band is the Ga antisite defect, GaAs, which acts as a 77 meV double acceptor.
Threshold Voltage Uniformity of GaAs-FETs on Ingot-Annealed Substrates
Authors: Kasahara Jiro , Arai Michio , Watanabe Naozo
Published: November 2005

Excellent threshold voltage uniformity, 27 mV in a 40 mm × 40 mm area and 14 mV in a 20 mm × 20 mm area, is obtained in a 2-inch undoped LEC-grown GaAs which has been ingot-annealed. Improvement in the uniformity is a consequence of the reduction of the number of the FET which has extraordinary threshold voltage. The extraordinary threshold voltage of the FET is not directly related to dislocations. Standard deviation obtained meets the requirement of GaAs LSIs or VLSIs.
A Voltage Bias Method for Studying the AC Josephson Effect at High Frequencies and for Application to Mixers
Authors: Matsui Toshiaki , Ishizu Mitsuo , Hayashi Risao
Published: November 2005

In experiments on the ac Josephson effect at high frequencies, the current bias method has the shortcoming of insufficient bias setting. We have here fabricated a voltage bias source, containing a current converter circuit, which has overcome this shortcoming. We attained with this voltage bias method a steady dc bias at optional voltage values andstable voltage scans with a high current sensitivity of 10 mV/µA, and have shown experimentally that by using this method, the dc bias of a Josephson mixer can be set at an optimum position independent of any conductance variation, including negative dynamic resistance.
4.2 K Operation of InAlAs/InGaAs Heterojunction Bipolar Transistor
Authors: Furukawa Akio , Baba Toshio
Published: November 2005

Low temperature operation of heterojunction bipolar transistor (HBT) is a key requirement for a HBT large scaled integrated circuit with low power dissipation and high speed switching, according to HBT scaling principle. Graded and uniform base InAlAs/InGaAs HBTs were fabricated and characteristics were measured from 300 K down to 4.2 K. Excellent HBT operations at 4.2 K were obtained for the first time, in both graded and uniform gap base structure. Comparing current gain of 1500 Å graded (7 kV/cm) base HBT with uniform base HBT, the former is 1.5 times higher than the latter at 300 K, and enhanced 4.5 times at 4.2 K. In the large built-in field case (21 kV/cm) of 500 Å base, current gain as high as 180 was obtained at 4.2 K. Graded base structure is necessary for high speed HBT operation at low temperatures.
Extremely Low Resistance Non-Alloyed Ohmic Contacts to n-GaAs Using Compositionally Graded InxGa1-xAs Layers
Authors: Nittono Takumi , Ito Hiroshi , Nakajima Osaake , Ishibashi Tadao
Published: November 2005

Silicon doping in lattice-mismatched In
x
Ga1-x
As (x=0, 0.2, 0.35, 0.65, 1.0) films grown on GaAs by MBE is studied. The maximum carrier concentration for In
x
Ga1-x
As is found to increase with the InAs mole fraction, x. Based on this result, the x dependence of the specific contact resistance, ρc, for non-alloyed ohmic contacts to n-GaAs using compositionally graded In
x
Ga1-x
As layers is also investigated. It is found that ρc decreases with increasing x for x≤0.65, and an extremely low specific contact resistance of 5×10-8 Ω·cm2 is obtained with 1.5×1019 cm-3 doped n+-In0.65Ga0.35As.
SiO2 Film Deposition by KrF Excimer Laser Irradiation
Authors: Nishino Shigehiro , Honda Hiroki , Matsunami Hiroyuki
Published: November 2005

Deposition of SiO2 on a Si substrate by irradiating SiH4–O2–N2 mixture gas with focused KrF excimer laser (wavelength: 249 nm) was carried out. The deposition rate was 300Å /min at a substrate temperature of 250°C. The deposition strongly depends on the substrate temperature, laser power and flow ratio of O2/SiH4, and these parameters have individual threshold values for the film deposition. Photo-initiation phenomena in SiO2 deposition are observed for the first time. The deposited film was evaluated by etching and infrared measurements together with electrical measurements.
A Method for Studying the Electric Field Enhanced Emission of Carriers from Deep Levels
Authors: Hwang In Duk , Choe Byungdoo
Published: November 2005

A spectroscopic method is proposed for studying the electric field enhanced emission of trapped carriers from deep levels. The resulting spectrum directly represents the effect of the electric field enhanced emission only, thus removing the intrinsic difficulty in treating the electric field enhanced emission from deep levels of large concentration. This method involves two steps of measurements of the ionized trap densities; in the first step the electric field pulse is applied to induce an enhanced emission, and in the second without the electric field pulse. Experimental results by this method have beengiven for the DX center in LPE Al068Ga0.32,As:Sn.
Barrier Height of Titanium Silicide Schottky Barrier Diodes
Authors: Kikuchi Akira
Published: November 2005

Schottky barrier diodes were fabricated on n-type Si surfaces with high resistivity. Barriers were produced by TiSi or TiSi2. Barrier height and resistivity of titanium silicide were examined in relation to phase differences identified by X-ray diffraction analysis. Barrier height was found to be unaffected by silicide phase.
A New Non-Contact Method to Measure Temperature of the Surface of Semiconductor Wafers
Authors: Tomita Takashi , Kinosada Toshiaki , Yamashita Tatuya , Shiota Masahiro , Sakurai Takeshi
Published: November 2005

A new direct and non-contact method to determine temperature of the surface of semiconductors by measurements of the refractive index using reflection ellipsometry is proposed. Use of a probing light larger than band gap in energy enhances the change of the refractive index, so that the temperature dependence of the index can be expressed by a simpie formula. Experimental results are in good agreement with the calculations. A temperature resolution of 0.3°C is expected with an ellipsometer resolving to the fourth decimal.
Observation of Room Temperature Current Oscillation in InGaAs/InAlAs MQW Pin Diodes
Authors: Kawamura Yuichi , Wakita Koichi , Asahi Hajime , Kurumada Katsuhiko
Published: November 2005

Oscillatory behavior of current in the forward current-voltage characteristics for InGaAs/InAlAs multiple quantum well pin diodes was observed at room temperature for the first time. This oscillation became extremely clear at low temperature (80 K), and the oscillatory bias voltage region shrank with decreasing the well numbers.
Carrier-Temperature and Wavelength-Switching in GaAs Single-Quantum-Well Baser Diode
Authors: Tokuda Yasunori , Fujiwara Kenzo , Tsukada Noriaki , Kojima Keisuke , Hamanaka Koichi , Nakayama Takashi
Published: November 2005

Carrier temperature (T
C) was estimated from the high-energy tails in the emission spectra for single-quantum-well laser diodes under pulsed operating conditions. The T
C in the lasers with 100 and 120 Å thick-GaAs active layers rose appreciably as the injection current increased, while the T
C remained at around the lattice temperature (T
L) for the 250 Å laser. It was suggested that the increase of T
C is essential to drive lasing-wavelength switching from the n=1 transition to the n=2 transition.
Boron Doping to Microeryslalline SiNx:H Films
Authors: Hasegawa Seiichi , Segawa Mizuki , Kurata Yoshihiro
Published: November 2005

Microcrystalline SiN
x
:H films were prepared by r.f. glow-discharge of SiH4–B2H6–N2–H2 mixtures with the gas volume ratio of N2/SiH4=0.03. The volume fraction of the crystalline phase and the crystallite size decrease with an increase in B-doping ratio, R
B. With increasing R
B, the dark conductivity σd increases up to a value larger than 10-3 Ω-1cm-1 (the activation energy E
a is 0.1 eV and the optical gap E
g is 1.9eV) at R
B=5×10-3 through the minimum σd smaller than 10-12 Ω-1cm-1 (E
a=1.1 eV, E
g=1.75 eV) at R
B around 10-4 to 10-3. The slope K in Tauc's relation increase with R
B.
Laser-Irradiation Effects on the Incorporation of Impurities in GaAs during MOVPE Growth
Authors: Ban Yuzaburoh , Takechi Masaru , Ishizaki Mamoru , Murata Hiroshi , Kukimoto Hiroshi
Published: November 2005

Laser-irradiation effects on the incorporation of n- and p-type impurities in GaAs have been studied by irradiating the substrate with an ArF excimer laser light during MOVPE growth. An n-type dopant source of TMSi is decomposed effectively by laser excitation, resulting in a dramatic increase in the carrier (electron) concentration. The decomposition of a p-type dopant source of DMZn is not influenced by laser irradiation at a growth temperature of 700°C. Si- or Zn-doped GaAs layers in the irradiated area are of high crystalline quality.
Morphology and Structure of Small CuAu Particles
Authors: Tsunoda Tatsuo , Osaka Toshiaki , Kimata Hiroyuki
Published: November 2005

Well-defined small particles of CuAu were prepared by an ultra high vacuum deposition system under well-controlled conditions. Their morphology and structure were investigated in detail by means of transmission electron microscopy. The particles had a tetragonal shape containing seven domains. The inner and largest domain comprised a disordered phase and the outer shell an ordered phase with three orientations characteristic of CuAu I. It is suggested that a peculiar structure exists at the interface of two adjacent ordered domains.
Excellent Negative Differential Resistance of InAlAs/InGaAs Resonant Tunneling Barrier Structures Grown by MBE
Authors: Inata Tsuguo , Muto Shunichi , Nakata Yoshiaki , Fujii Toshio , Ohnishi Hiroaki , Hiyamizu Satoshi
Published: November 2005

Light electron effective mass was found to be a very important parameter for improving the negative differential resistance (NDR) of a resonant tunneling barrier (RTB) structure. An InAlAs (41 Å)/InGaAs (61.5 Å)/InAlAs (41 Å) RTB structure, lattice-matched to Ink, has been grown for the first time by MBE and dramatically improved NDR has been achieved. Peak current density as high as 2.2×104 A/cm2 with an excellent peak-to-valley current ratio of 11.7 was obtained at 77 K, which is the best data ever reported so far for any RTB structures.
Effect of Monatomie Hydrogen in Zinc Phosphide
Authors: Suda Toshikazu , Kuroyanagi Akio
Published: November 2005

Hydrogen passivation of zinc phosphide (Zn3P2) has been shown to neutralize native deep defects in terms of deep level transient spectroscopy and current-voltage measurements. Native deep hole traps with activation energies of 0.20 eV and 0.49 eV from the top of the valence band disappear by the passivation due to hydrogen plasma; the concentration of 0.36 eV hole trap is also reduced significantly. The hydrogenation has improved the current-voltage characteristics of Zn3P2 Schottky diodes dramatically: reverse leakage current of as-grown samples is reduced by two orders of magnitude after hydrogenation.
High Speed Laser Beam Scanning Using an Acousto-Optical Deflector (AOD)
Authors: Hosaka Sumio , Seya Eiichi , Harada Tasuo , Takanashi Akihiro
Published: November 2005

The cylindrical lensing effect in high-speed laser-beam scanning using an acousto-optical deflector AOD was theoretically and experimentally investigated. As a result, both a static and a dynamic cylindrical lensing effect was found during high-speed laser-beam scans. A compensation for a cylindrical lensing effect was proven to be very important for a realization of high-speed laser-beam scanning. Examples of this compensation are an improvement in the voltage-frequency converter and the use of a cylindrical lens behind the AOD. With such compensation, the focal position deviation from the nominal focal plane could be suppressed to remain within 4 µm when the laser beam was scanned over about 300 µm on the focal plane at a 10 m/s scanning speed and a 20 kHz ramp signal frequency.
Graphical Representation of the Piezoresistance Coefficients in Silicon-Shear Coefficients in Plane
Authors: Kanda Yozo
Published: November 2005

The shear piezoresistance coefficients π'66, π'16 and π'26 of p- and n- type silicon are plotted as a function of the crystal directions for orientations in the (100) plane.
Silicon pressure and other mechanical sensors with a four-terminal gauge, such as a Hall effect-type device, utilizing the shear stress have been of much interest. The outputs of the sensors are proportional to the shear piezoresistance coefficient π'66.
Intrinsic Gettering of RIE Damage on Silicon Studied by Scanning DLTS and EBIC Methods
Authors: Ikuta Kenji
Published: November 2005

The degradation of silicon substrates due to reactive ion etching (RIE) damage and its elimination by intrinsic gettering (IG) are studied using scanning DLTS (SDLTS) and EBIC methods in an SEM. The SDLTS study clarifies that a hole trap ofEv+0.37 eV is introduced uniformly by RIE. Surface stacking faults are grown from latent defects associated with the trap during subsequent annealing. The EBIC analysis can predict macroscopic lifetime degradation due to the defect generation. IG is found to be successful in eliminating the degradation, when subsequent annealing is performed in O2, but not successful in N2annealing. The gettering mechanism for RIE damage is also discussed in terms of the dependence on the annealing ambient.
“Monomorph Actuators” Using Semiconductive Ferroelectrics
Authors: Uchino Kenji , Yoshizaki Mikihiko , Kasai Kiyoshi , Yamamura Hiroshi , Sakai Naomichi , Asakura Hiroshi
Published: November 2005

A new type of bending actuator, “monomorph”, is proposed by using a single plate of semiconductive piezoelectric ceramics. The principle of bending originates from the nonuniform distribution of the electric field in a single plate caused by the semiconductor–metal electrode contact. Monomorph characteristics are exemplified in lead zirconate based and barium titanate ceramics. A bend curvature comparable to that of conventional piezoelectric “bimorphs” can be obtained.
Integrated DC–SQUID Magnetometer
Authors: Nakanishi Masakazu , Koyanagi Masao , Kosaka Shin , Shoji Akira , Aoyagi Masahiro , Shinoki Fujitoshi
Published: November 2005

A magnetometer using a refractory material integrated with a pickup coil and a DC superconducting quantum interference device (DC–SQUID) has been developed for biomagnetic applications. It has an overall size of 8 ×9 mm2 and a field resolution of less than 40 fT/ √Hz which is limited by the electronics at frequencies above 20 Hz.
Improvement of Selective Film for Stainless Steel Solar Collector
Authors: Ohno Jiro , Abe Seizaburo , Kobayashi Hisashi
Published: November 2005

A new selective film for a stainless-steel solar collector has been developed. The selective film is produced by a chemical conversion process, the bath of which is a mixed acid of Na2Cr2O7 and H2SO4. Examining the conversion process, it was found that large amounts of Fe and Cr were embedded in an oxide film as the metallic state. A theoretical analysis shows that metals within an oxide layer form a film with a graded optical index and that selectivity is realized. When the concentration of metals within an oxide film increases linearly, excellent selectivity is obtained. The selectivity was evaluated by the reflectance and the temperature rise of samples using a hot box placed in the sunlight. The color of the film treted by the new bath is black; this new black film shows a selectivity that is as good as that of black chrome film formed on a Cu substrate.
The Role of Stacked Insulating Layers on Thin-Film Electroluminescent Devices
Authors: Ohwaki Junichi , Yamauchi Noriyoshi , Kozawaguchi Haruki , Tsujiyama Bunjiro
Published: November 2005

The charge versus applied voltage (Q–V) characteristics of a thin-film electroluminescent (TFEL) device with an Al/SiO2/Ta2O5/ZnS/Ta2O5/ITO/Glass structure are investigated. The results for a stacked insulating layer TFEL device are summarized as follows. The maximum charge (Q
max) of the TFEL device is determined by the highest Q
max of insulators. The SiO2 insulating layer used in this study shows that the dielectric avalanche breakdown and the electric field of the film is clamped in the region above its own breakdown field strength under current conditions limited by the Ta2O5 insulating layers. The TFEL device shows a hexagonal Q–V loop in high electric fields.
Fluorescence from Pearls and Shells of Black Lip Oyster, Pinctada Margaritifera, and Its Contribution to the Distinction of Mother Oysters Used in Pearl Culture
Authors: Miyoshi Tadaki , Matsuda Yasunori , Komatsu Hiroshi
Published: November 2005

The fluoresence of pearls and shells of Pinctada margaritifera (black lip oyster) has been measured in order to distinguish the species of mother oysters which produce those pearls. A distinction is possible for pearls of P. margaritifera from those of Pinctada fucata and Pinctada maxima using a difference in the fluoresence spectra; this difference is caused by the presence or absence of porphyrin in pearls, respectively. However, the distinction between P. margaritifera and Pteria penguin, both of which have porphyrin in nacre, is difficult by measuring the fluorescence spectra. It is achieved by measuring the optical reflection spectra, since P. margaritifera shows a peculiar dip at 700 nm.
Magnetic Anisotropy and Magneto-Optic Kerr Spectra of Amorphous Ho–Co Thin Films
Authors: Lu Mu , Choe Young-joon , Tsunashima Shigeru , Uchiyama Susumu
Published: November 2005

The substrate bias dependence of the uniaxial anisotropy Ku in sputtered Ho
x
Co1-x
films has been studied in the bias voltage range 0 to -100 V. K
u is almost constant in the V
b range 0∼-50 V and increases abruptly above -50 V, as in the case of Tb–Co. The increment of K
u between -50 and -100 V in Ho–Co is about one third of that of Tb–Co; this can be understood under the asumption that K
u originates from an anisotropic 4f electron cloud. The magneto-optic Kerr spectra of Ho–Co films prepared by co-evaporation have also been measured in the wavelength range 250 to 700 nm. In the short-wavelength region, the Kerr rotation of Ho–Co decreases with decreasing wavelength and approaches zero more rapidly than in the case of Y–Co. This is considered to be due to a negative contribution of Ho to the Kerr rotation of Ho–Co.
Influence of Gallium Sources on Impurity Doping in Gas Source MBE GaAs
Authors: Misawa Shunji , Okumura Hajime , Yoshida Sadafumi
Published: November 2005

The difference of gallium sources, elemental gallium (Ga) and triethylgallium (TEG) on impurity doping in GaAs grown by gas source MBE using AsH3 gas has been studied. Unintentionally doped GaAs epilayers show p- and n-type conductivities, respectively, with and without a Liq.N2 trap in oil diffusion pump evacuation system when TEG was used as a gallium source. On the other hand, all the GaAs epilayers grown using Ga show p-type conductivity. Si doping efficiency by use of SiH4 gas for the growth using TEG is about 6-times higher than that for growth using Ga. The differences of impurity doping in gas source MBE using TEG and Ga are discussed based on the results of photoluminescence and secondary ion mass spectroscopic measurements.
Characteristics of Microwave Plasma and Preparation of a-Si Thin Film
Authors: Fujita Hiroharu , Handa Hiroshi , Nagano Masamitsu , Matsuo Hisao
Published: November 2005

The characteristics of a plasma produced by launching 2.45 GHz microwave beams through a glass of pure argon gas have been studied. A direct observation of the microwave electric field with a loop antenna placed in the tube revealed that a plasma is produced at the microwave inlet. The threshold condition for a microwave discharge was experimentally obtained under a wide range of argon gas pressures and magnetic fields. The threshold gas pressure strongly decreases as the magnetic field approaches the electron cyclotron resonance (ECR) condition. By mixing SiH4 gas (20%) with argon gas, an amorphous silicon thin film can be prepared in the microwave plasma. The impurity content and the morphology of the film depend on the substrate location.
Development of a Large Bucket Plasma Source
Authors: Oka Yoshihide , Guharay Samar K. , Sakurai Keiichi , Kaneko Osamu , Kuroda Tsutomu
Published: November 2005

A large bucket-type plasma source has been developed for a neutral beam injector. An ion current density of 0.25 A/cm2 in a hydrogen plasma was achieved with a density uniformity of better than ∼10% over an area of 15×60 cm2 at about 100 kW of arc power in pulsed operation for 1s. Plasma density profiles and the discharge voltage-current characteristics, etc., were studied by varying the geometrical parameters of a tungsten filament i.e., the disposition, number, diameter, and shape. The profile was affected by the filament disposition and the gas pressure. A measure of the gap length between filaments to generate a dense uniform (< 10%) plasma was roughly 14-22 cm. An experimental scaling relation of the arc power is discussed; the arc power for the same plasma density appears to increase with an increase in the total loss-area in various sources.
Efficient Shell Implosion and Target Design
Authors: Murakami Masakatsu , Nishihara Katsunobu
Published: November 2005

A theoretical model is presented that describes the spherical ablative implosion under a constant mass ablation rate. The implosion dynamics is found to be determined only by one parameter, which we call the implosion parameter. An analytical formulation for the hydrodynamic efficiency is obtained as a function of the implosion parameter. The theory is applied to shell implosions driven by steady black-body radiation, and compared with computer simulations. As a result, we obtain scaling laws of the optimum shell radius and the aspect ratio, leading to a maximum hydrodynamic efficiency as a function of the radiation intensity and its pulse duration. Stability requirements on those scaling laws and the relation between the transformation efficiency and the aspect ratio are also discussed.
Formation of Ohmic Contacts to n-GaAs by Solid Phase Epitaxy of Evaporated and Ion Implanted Ge Films
Authors: Fukada Tsuyoshi , Asano Tanemasa , Frukawa Seijiro , Ishiwara Hiroshi
Published: November 2005

Ge films evaporated on GaAs(100) substrates have been amorphized by ion implantation and recrystallized epitaxially in the solid phase. Ohmic characteristics have been obtained in Ge/n-GaAs heterostructures by implantation of As+ or P+ in Ge and Si+ at the interface. A two-step annealing method was found to be effective to obtain ohmic characteristics. In two-step annealing, the first annealing step at low temperature is for solid phase recrystallization of Ge films; the second step involves rapid high-temperature annealing in order to activate the implanted species. It has also been found that interdiffusion should be minimized in order to obtain good ohmic characteristics.
Microwave-Excited Plasma CVD of a-Si:H Films Utilizing a Hydrogen Plasma Stream or by Direct Excitation of Silane
Authors: Watanabe Takeshi , Tanaka Masahiro , Azuma Kazufumi , Nakatani Mitsuo , Sonobe Tadashi , Shimada Toshikazu
Published: November 2005

The microwave-excited plasma CVD of a-Si:H films, in which SiH4 was decomposed by a plasma stream of hydrogen or by direct excitation at low gas pressures (10-4 to 10-3 Torr), was examined and compared with a previously studied Ar plasma stream method. It was clarified that an Ar plasma stream was not necessary to obtain highly photoconductive a-Si:H films. However, the deposition characteristics in these deposition methods were different from the Ar plasma stream method. On the other hand, the influence of the hydrogen plasma stream was not apparent when the SiH4 flow rate was high, suggesting an ionization cross-section dependence of the plasma discharge.
Direct Patterning and Electrical Properties of Phthalocyanines Thin Films Prepared by Langmuir-Blodgett and Spin Cast Techniques
Authors: Fujiki Michiya , Tabei Hisao , Imamura Saburo
Published: November 2005

The patterning and electrical properties of thin films based on two new highly soluble nickelphthalocyanines involving four long alkyl amides (AmPc1 and AmPc2) have been examined. The films were prepared using the Langmuir-Blodgett and spin cast techniques. The film conductivities increased by 2–4 orders of magnitude upon iodine vapor exposure and reached ca. 10-6 S cm-1. Both the AmPc1 and AmPc2 thin films showed negative patterning features to electron beam (EB) dose, and excellent resistance to plasma-assisted dry etching. The AmPc2 possesses high contrast in a LB film (γ=3.8) and high reactivity (D
0=3.5 µC cm-2) in a spin cast film. The fine patterns in the AmPc2 spin cast film have been fabricated down to lines with widths of 0.8 µm (with a 0.8 µm, spacing) using EB irradiation and wet etching, while (probably) maintaining the semiconducting properties of the Pc ring moieties without decomposition.
Analysis of a Newly Developed Damped-Oscillation Rheometer: Newtonian Liquid
Authors: Murata Tadayoshi , Date Munehiro , Kaibara Makoto
Published: November 2005

The behavior of a newly developed damped-oscillation rheometer was analyzed for Newtonian liquids from both theoretical and experimental points of view. This rheometer consists, essentially, of a cylindrical tube suspended from a torsion wire that is filled with the liquid to be tested. In order to determine the relationship between the rheological parameters of the liquid and the period or the logarithmic damping factor measured by this rheometer, a Newtonian liquid was considered as a first test liquid. Based on various assumptions, the equations of motion for the liquid and the cylindrical tube were solved simultaneously. Numerical solutions and approximate analytical solutions valid for certain ranges of the parameters were obtained. The results are compared with experimental results which we measured using this rheometer.
“Monomorph” Characteristics in Lead Zirconate Based Ceramics
Authors: Uchino Kenji , Yoshizaki Mikihiko , Kasai Kiyoshi , Yamamura Hiroshi
Published: November 2005

“Monomorph” characteristics, i.e. bending motions of a single ceramic plate have been investigated in the PbZrO3-(K1/2Bi1/2)ZrO3 solid solutions. The composition dependence of the bending deformation measured is explainable on the bases of the semiconductor and field-induced strain properties. Also, the bending mechanism could be analysed by measuring the lattice parameter change with an applied electric field.
Dependence of Laser-Induced Damage Threshold of Anti-Reflection Coatings on Substrate Surface Roughness
Authors: Nose Yukari , Kato Yoshiaki , Yoshida Kunio , Yamanaka Chiyoe
Published: November 2005

The geometrical shapes of damage sites in 5-layer SiO2/ZrO2 anti-reflection (AR) coatings generated by 1 µm laser irradiation have been accurately determined. The damage can be classified into two types: deep damage and shallow damage, the former having a lower threshold. The dependence of the damage threshold of deep damage on the substrate surface roughness is given. It is suggested that the presence of absorption centers embedded in the pores or scratches on the surface of the substrate is responsible for determining the damage threshold. Possible approaches that will lead to stronger AR coatings are proposed.
Preparation of High Remanence TbFe Films
Authors: Higashi Isao , Numata Takuhisa , Inokuchi Seiji , Sakurai Yoshifumi
Published: November 2005

The remanence of amorphous TbFe films with perpendicular anisotropy deposited by several deposition methods was investigated. The uniaxial anisotropy was enhanced in films deposited onto rotating substrates. The coercivity increased with dual gun sputtering compared to single gun sputtering. The remanence did not depend on the anisotropy directly but was mainly related to the wall coercivity. In dual gun rf magnetron sputter-deposited films onto rotating substrates, the wall coercivity was so large that magnetization rotation dominated the magnetization reversal, resulting in high remanence. The wall coercivity also increased in laminated films. A high remanence of 300 Gs with a residual ratio of 1 has been obtained in Tb31Fe69 films produced with a repetition of the deposition of a 0.5 µm thick lamina and the time intervals between the sputtering of each lamina.
Two Dimensional Resolution Improvement of an Imageguide by Maximization of Wavelength Multiplexing
Authors: Itoh Yoshitoshi
Published: November 2005

This paper describes a new technique for improving the resolution of images transferred through an imageguide. Wavelength multiplexing is used to increase the number of picture elements transferred through the glassfiber in an imageguide. The direction of dispersion used in wavelength multiplexing is controlled in order to maximize the number of picture elements. In an experiment, the resolution of a conventional imageguide comprising 30,000 closely-packed hexagonally arranged fibers (core: cladding=9 µm: 9 µm) was improved by a factor of 2.5 using wavelength multiplexing.
A Periodic Layered Structure Laser Using an Electro-Luminescent Type Excitation
Authors: Ishikawa Toshiaki
Published: November 2005

A periodic layered structure laser is newly proposed. One period of the structure consists of two types of layers: one is for transparent electrode (or an insulator layer) and the other is for a laser medium which contains luminescence centers. Laser pumping is produced by electron impact excitation using carrier electrons accelerated by an externally applied ac or dc voltage through a pair of transparent electrodes. The electromagnetic waves in the laser medium are dealt with using the Kronig-Penny model. The reflectivity and transmittivity of the laser medium are calculated around the Bragg frequency. The minimum threshold gain is obtained at the Bragg frequencies. On the basis of the rate equations analogous to the gass phase laser, the minimum number of accelerated electrons required for the population inversion and the over all efficiencies are estimated.
Effect of Plasma Opacify on the Doppler-Free Polarization Spectrum in a Hydrogen Plasma
Authors: Arata Yoshiaki , Miyake Shoji , Matsuoka Hidesato
Published: November 2005

In a low-density hydrogen plasma, the saturation behavior of the Hα line emission has been studied by Doppler-free polarization spectroscopy with a pulsed high-power tunable laser. Spectral profiles of the Doppler-free fine structure components of the Hα line were found to be largely distorted by the effect of reabsorption in the plasma. A simple calculation of the spectral profiles, while taking into account the effect of the plasma opacify in the saturation condition, is in good agreement with the experimental result.
High-Quality ZnSe Film Growth by 0.1-atm MOVPE under the Diethylzinc Diffusion-Limited Condition
Authors: Shibata Noriyoshi , Ohki Akira , Zembutsu Sakae
Published: November 2005

The effects of the growth conditions on the growth rate, crystallographic and luminescence properties were investigated for ZnSe film growth by metalorganic vapor phase epitaxy at 0.1 atm using diethylzinc and H2Se. It was shown that high-quality epitaxial layers can be grown under the diethylzinc diffusion-limited condition over temperatures ranging from 250 to 500°C. These layers exhibit dominant blue photoluminescence at 77 K. However, the optimum growth temperature for ZnSe layers having a smooth surface and high crystallographic properties is restricted to within the region between 300 and 400°C.
On Shifting of Plowed Plasma to Back of Current Sheath in Implosion Phase of Theta-Pinch
Authors: Ogi Sukeomi , Shiratani Masaharu , Takamatsu Masahiro , Watanabe Yukio
Published: November 2005

In order to study a phenomenon that the plowed plasma had shifted to the back of the current sheath region in the implosion phase of a theta pinch, computer simulations were performed by using MHD equations consisting of electrons, ions and atoms. The simulations clarified the mechanism by which the plasma plowed in front of the current sheath had shifted to the back of the sheath. The phenomenon is caused by a decrease in the electron temperature or a resistivity enhancement due to inelastic collisions, especially excitation collisions, of electrons with atoms. The shifted plasma still implodes with the E
θ × B drift velocity. The charge exchange has little effect on the phenomenon.
Blue Electrochromism in Viologen-Cyclodextrin/Ferrocyanide System
Authors: Yasuda Akio , Mori Hiroshi , Mizuguchi Jin
Published: November 2005

Electrochromic properties of a variety of alkylviologen compounds have been investigated in the presence of α-, β-and γ-cyclodextrins in the potassium ferrocyanide and sodium hypophosphite system. A blue electrochromism was newly observed in the systems of hexylviologen with α- or β-cyclodextrin and heptylviologen with α- and β-cyclodextrin. The color shift from red-violet to blue, due to the presence of cyclodextrin, is tentatively explained by a model of the solvent effect, in which a viologen is included in a cyclodextrin cavity and is thus exposed to a weaker polar field than in water. The electrochromic characteristics obtained are as follows: driving voltage of 0.95 V, contrast ratio of 9:1 and write-erase cycles of over 107.
Filling a Double-Cusp Magnetic Container with Plasmas Produced by a Long-Pulse CO2-Laser and Its Confinement Properties
Authors: Ogasawara Munehiro , Sekiguchi Tadashi , Kohno Tetsushi
Published: November 2005

A laser-produced beryllium plasma with an effective volume of nearly 1 litre has been produced at the central, nearly uniform magnetic field region of a double-cusp magnetic field configuration by using a high-power CO2-laser with a relalively long pulse duration (∼2 µs) and total output energy of about 200 J was obtained and its plasma-filling property as well as confinement was studied. It has been shown that (1) the employment of this longer-pulse laser is effective to produce plasmas containing a large number of ions and to maintain a high temperature within a magnetic container, (2) a higher plasma-beta region (β>0.5) is restricted axially only in the vicinity of the position of plasma production, and (3) a confinement model of the double-cusp magnetic container for the resulting low-beta plasma is discussed in the light of the obtained experimental results. The physical reason for item (2) above is also considered.
First Passage Time Intervals of Gaussian Processes
Authors: Perez Hector , Kawabata Tsutomu , Mimaki Tadashi
Published: November 2005

Abstract- The first passage time problem of a stationary Guassian process is theretically and experimentally studied. Renewal functions are derived for a time-dependent boundary and numerically calculated for a Gaussian process havinga seventh-order Butterworth spectrum. The results show a multipeak property not only for the constant boundary but also for a linearly increasing boundary. The first passage time distribution densities were experimentally determined for a constant boundary. The renewal functions were shown to be a fairly good approximation to the distribution density over a limited range.
Determination of the Total Number of Ions Confined in an RF Ion Trap
Authors: Yoda Jun
Published: November 2005

The total number of N2 ions confined in an rf ion trap was measured at various pressures of N2 gas. It was found that the total number of the trapped ions was independent of the pressure of N2 and was determined by the maximum potential depth of the ion trap.
Mode-Selective Directional Coupler for High Power Microwave Measurements
Authors: Saito Teruo , Masabayashi Hirotaka , Kariya Tsuyoshi , Kiwamoto Yasuhito , Miyoshi Syoichi
Published: November 2005

An improved directional coupler has been designed, fabricated and tested in order to measure the high-level power of microwave produced by a gyrotron. It has shown a sufficient function requisite in electron cyclotron resonance heating experiments of magnetically confined plasmas. The results of tests under practical experimental conditions are described and various points to be taken in the design of a directional coupler are given.
Multiple Slit Lens for Focusing-Deflection of Charged Particles
Authors: Kishi Tohru , Yokota Harumitsu , Katayama Katsuo
Published: November 2005

The focusing-deflection lens action of a five-slit lens was examined. When the first three pairs and the remaining three pairs of electrodes with central pairs in common were operated as focusing-deflection and focusing lenses, respectively, an incident charged beam could be deflected in good focused condition.
Optical Characterization of Undoped a-Si:H Prepared by Photo-CVD and GD Techniques
Authors: Kawasaki Satoshi , Sato Katsuaki , Suzuki Kazuhiko , Takeuchi Hiroshi , Kuroiwa Koichi , Tarui Yasuo
Published: November 2005

We have optically characterized undoped a-Si:H films prepared by photo-CVD and GD techniques under various deposition conditions. Photoluminescence(PL) and transmission spectra were measured at 77 K, from which the peak energy E
p of the main PL band and the optical absorption edge E
gopt could be deduced. We have obtained the Urbach energy E
0 by means of photothermal deflection spectroscopy(PDS) at room temperature. The differences ΔE between E
p and E
gopt were plotted against E
0 for films prepared under various conditions, from which it was found that the same linear relation holds between ΔE and E
0 commonly for films prepared by both techniques. We conclude that the increase of ΔE in films deposited at a low substrate temperature is mainly caused by a broadening of the tail states owing to disorder in the amorphous network.
A Boundary Layer Model for the MOCVD Process in a Vertical Cylinder Reactor
Authors: Shibata Noriyoshi , Zembutsu Sakae
Published: November 2005

The transport process in metalorganic chemical vapor deposition (MOCVD) is investigated for a vertical reactor where two kinds of reactants are mixed just above the horizontally-attached substrate. A boundary layer model is developed and the epitaxial growth of the compound semiconductor is described. The model predicts that the growth rate is a function of reactant partial pressure, boundary layer thickness and the degree of mixing. It also predicts that uniformity in thickness is obtained by controling the homogeneity of mixing. Results of experimental studies on ZnSe epitaxial growth rate agree well with the calculated growth rate.
Waveguide Coupling during Lower Hybrid Current Drive in a Tokamak
Authors: Ohkubo Kunizo , Matsumoto Kazunori
Published: November 2005

By using a lower hybrid current drive, changes in the amplitude and phase of reflected signals at the four-waveguide grill as well as decreases in the edge plasma density measured by double probes could be monitored. The influence of the plasma density and its gradient at the grill mouth on the coupling between waveguides and a plasma was investigated using a simplified linear grill theory based on a step plus ramp density model. It was confirmed from a comparison with the theoretical analysis that changes in waveguide coupling during current drive were mainly caused by a decrease of the density in the scrape-off plasma.
A Vortex Transitional NDRO Josephson Memory Cell
Authors: Tahara Shuichi , Wada Yosifusa
Published: November 2005

A new vortex transitional NDRO memory cell has been proposed for use as a high-speed cache memory. The memory cell consists of two superconducting loops with one Josephson junction and a two-junction interferometer gate. The superconducting loop stores single-flux quantum. The interferometer gate operates as a sense gate. The memory cell employs a vortex transition in the superconducting loop for the writing and reading of data. The sense gate current margin increases to ±38% since the coupling magnetic flux is amplified by the vortex transition for nominally designed cell parameters. The memory cell operates with a ±33% address signal current margin. This paper describes the memory cell design and the dynamic behavior of computer simulations.
Color Electroluminescent Devices Prepared by Metal Organic Chemical Vapor Deposition
Authors: Hirabayashi Katsuhiko , Kozawaguchi Haruki , Tsujiyama Bunjiro
Published: November 2005

This paper discusses the preparation of AC thin film ZnS:Tb (green), Sm (red) and Tm (blue) color electroluminescent devices by metal organic chemical vapor deposition, using dimethylzinc and H2S as source gases. A new doping method for luminescent centers was used. This was accomplished by evaporating TbF3, SmF3 SmCl3 and TmF3 after they had been heated to their melting points during the growth of ZnS in a MOCVD reactor. The maximum brightnesses of ZnS:TbF3, ZnS:SmCl3 and ZnS:TmF3 are 5000, 1000 and 10 cd/m2. The ZnS:SmCl3 EL devices showed a deeper red chromaticity than the ZnS:SmF3 EL ones.
Three-Dimensional Computer Simulation of Propagating Vertical Bloch Line Pair in Magnetic Garnet Film
Authors: Fujita Enji , Konishi Susumu
Published: November 2005

The structure of a vertical Bloch line has been studied by using a three-dimensional computer simulation to clarify the static and dynamic behaviors in Bloch line memory. The Bloch line shows a 2π radian rotation of wall magnetization along the wall on one side of the surface, and disappears at the other surface. The width is nearly uniform in spite of the nonuniformity of the rotation angle. Bloch line propagation under potential wells was simulated for a bias pulsed field. The potential wells were generated by a patterned high coercive-force film located on the garnet surface. It was found that the Bloch line pairs propagated smoothly under such a nonuniform potential well without showing any serious distortion.
Stimulated Resonance Raman Scattering of Cyanine Dye DDTCB
Authors: Ohtsuka Masao , Oguchi Masanobu
Published: November 2005

Very intense, stimulated resonance Raman scattering (SRRS) was observed in an ethanol solution of cyanine dye, 3,3'-diethyl-6,7,6',7'-dibenzothiadicarbocyanine bromide (DDTCB) upon excitation by a Q-switched ruby laser. The number of SRRS lines was fifteen, the most intense SRRS line being observed at 1252 cm-1. A comparison of DDTCB with some other cyanine dyes for which SRRS has already been reported under the same experimental conditions revealed DDTCB to be first in both the number of lines and intensities of the SRRS.
In addition, spontaneous Raman scattering (SpRS) was measured for these dyes under varied excitation wavelengths (488.0, 514.5 and 632.8 nm) in order to investigate the resonance Raman effect. DDTCB showed stronger relative intensities and a greater resonance Raman effect than the other cyanine dyes.
Analysis of Change in Optical Transmission Spectra Resulting from Ag Photodoping in Chalcogenide Film
Authors: Kawaguchi Takeshi , Masui Kanji
Published: November 2005

Photodoping in a thin sample of Ag–Ge30S70 was studied by an optical transmission measurement. Changes in the optical transmission spectra were analyzed on the bases of a uniform distribution of dissolved Ag. This study suggests that the spectra of thin samples are not modulated by the interference effect over a wavelength range of 350–800 nm. The amount of photodoped Ag is quantitatively estimated from values of ln [T(t)/T(0)], where T(t) is the transmission after exposure to light for time t. There is a specific wavelength at which the transmission is practically independent of the irradiation time; traces of the spectra reach a point at this wavelength. This point is called an isotransmission point and is denoted λ*. The condition that λ* appears in the spectra was derived theoretically. The isotransmission point is useful for estimating the thicknesses of an Ag-doped layer.
Nonlinear Polarization Changes in a Birefringent Fiber
Authors: Kimura Yasuo , Nakazawa Masataka
Published: November 2005

The nonlinear evolution of the polarization state along a birefringent fiber has been numerically investigated using the Poincaré sphere representation. The polarization changes of intense light in a birefringent fiber are governed by a competition between intrinsic and intensity-induced birefringence. When the intrinsic birefringence is cancelled by the intensity-induced birefringence, the evolution of the polarization state along the fiber is sensitive to a small perturbation, i.e., a fluctuation of the birefringence. The trajectories of the polarization state exhibit a complex behavior.
On the Reaction Kinetics in a Mercury Photosensitized CVD of a-Si:H Films
Authors: Matsui Yasuji , Yuuki Akimasa , Morita Noriko , Tachibana Kunihide
Published: November 2005

The reaction kinetic processes for mercury photosensitized CVD (Hg*–CVD) in silane were analyzed using a time-dependent, one-dimensional calculation based on mass-, momentum- and energy-conservation equations, including simplified surface reactions such as radical adsorption and hydrogen elimination from the substrate. A good agreement between the measured and the calculated time-varying concentrations of species provides sufficient validity regarding the present model. It is also shown that the saturation of the SiH4 decomposition observed by many authors in closed systems can be explained by the abstraction of SiH4 from the surfaces by radicals peculiar to the Hg*–CVD (e.g., HgH); gas-phase reactions are significantly influenced by surface reactions when the volume-to-surface ratio becomes small.
Ferroelectric Critical Behavior in the Copolymers of Vinylidene Fluoride and Trifluoroethylene from Nuclear Spin-Lattice Relaxation Studies
Authors: Ishii Fumiaki , Odajima Akira
Published: November 2005

An anomalous increase of the reciprocal spin-lattice relaxation time T
1
-1 near the Curie temperature T
c(↓) during thecooling process of the vinylidene fluoride (VDF) and trifluoroethylene (TrFE) copolymer was investigated by applying an effective Ising spin model to the configuration fluctuation of the trans segment. The anomalous part of T
1, (T
1)fluc, of the form A(T-T
0)1/2, where T
0 is the characteristic temperature, was derived in terms of the random phase approximation in the Ising model.T

c
(↓) for the VDF and TrFE copolymer was almost equal to T
0. By using the observed value of (T
1)fluc, the effective nearest-neighbor distance between fluctuating trans segments and the correlation length were calculated. The contribution of the nearest-neighbor interaction to the polarization fluctuation is discussed for the VDF contents of 52, 65 and 72 mol%.