bluuebunny/crossref_metadata_2025 huggingface dataset:
High Speed F-N Operated Volatile Memory Cell with Stacked Plasma Enhanced Chemical Vapor Deposition (PECVD) Nanocrystalline Si Layer Structure
Authors: Shen Shih-Jye , Lin Chrong-Jung , Hsu Charles Ching-Hsiang
Published: October 2002

A volatile memory structure with nanocrystalline Si (nc-Si) layer and auxiliary floating
polysilicon gate is proposed. The charges are injected through tunnel oxide and nc-Si layer by
Fowler-Nordheim (F-N) tunneling and then stored in the stacked structure. The nc-Si layer
improves programming speed during F-N operation and the extended structure with floating gate
improves the limited charge storage volume and makes the memory device with distinct threshold
voltage window. The reliability of this cell is shown to be sufficient for using as dynamic memory.
Locking of Relaxation Oscillation Frequencies and Chaos in a Free-Running Two-Mode Nd:YVO 4 Laser
Authors: Kenju Otsuka Kenju Otsuka , Yusuke Asakawa Yusuke Asakawa , Ryoji Kawai Ryoji Kawai , Siao-Lung Howng Siao-Lung Howng , Jyh-Long Chern Jyh-Long Chern
Published: October 2002

The dynamics of relaxation oscillations has been investigated in a free-running
laser-diode-pumped microchip multimode Nd:YVO4 laser. The locking
of relaxation oscillation frequencies, and quasi-periodic and chaotic oscillations have been observed in two-mode regimes. The cross-gain coupling among modes is proposed to explain the observed instabilities.
Three-Dimensional Optical Data Storage in Vitreous Silica
Authors: Watanabe Mitsuru , Sun Hongbo , Juodkazis Saulius , Takahashi Toshimasa , Matsuo Shigeki , Suzuki Yoshihisa , Nishii Jyunji , Misawa Hiroaki
Published: October 2002

To achieve high bit densities (>10 GB/cm3) in optical memory, we accomplished a three-dimensional
optical data storage system using vitreous silica as the recording material.
We succeeded in high-density optical recording by focusing pulsed laser beams of 532 nm
(full width at half maximum [FWHM] 30 ps) and 400 nm (150 fs). A recording
density of 72.9 GB/cm3 was achieved, which corresponded to that of 100 compact disks,
on a glass plate of (2×2) cm2 and 2.2 mm thickness. We found that the optical damage
of silica occurs within 400 ps after irradiation by a single pulse for 30 ps at 532 nm.
Three photoluminescence bands were found in the photomodified silica at 283 nm, 468 nm
and 558 nm. All the three bands showed similar photoluminescence excitation spectra,
i.e. a peak related to oxygen vacancy absorption at 250 nm.
Extremely High Quantum Photoyield from Cesiated Polycrystalline Diamond Films
Authors: Niigaki Minoru , Hirohata Toru , Mochizuki Tomoko , Uchiyama Shoichi , Kan Hirofumi , Hiruma Teruo
Published: October 2002

An extremely high quantum photoyield, as high as 70% at the photon energy of 10 eV, was
observed from cesiated polycrystalline diamond films. The threshold photon energy of 5.5 eV or
less was observed. The results suggest that the cesiated polycrystalline diamond surface has a true
negative electron affinity. In contrast, a quantum photoyield of 17% at the photon energy of 10 eV
was observed for a hydrogenated polycrystalline diamond film. The threshold photon energy of 5.5 eV or less was also observed, as in the cesiated one. It seems that the hydrogenated polycrystalline
diamond surface has an effective negative electron affinity.
Stress and Defect Control in GaN Using Low Temperature Interlayers
Authors: Amano Hiroshi , Iwaya Motoaki , Kashima Takayuki , Katsuragawa Maki , Akasaki Isamu , Han Jung , Hearne Sean , Floro Jerry A. , Chason Eric , Figiel Jeffrey
Published: October 2002

In organometallic vapor phase epitaxial growth of GaN on sapphire, the role of the
low-temperature-deposited interlayers inserted between high-temperature-grown GaN layers was
investigated by in situ stress measurement, X-ray diffraction, and transmission electron
microscopy. Insertion of a series of low temperature GaN interlayers reduces the density of
threading dislocations while simultaneously increasing the tensile stress during growth,
ultimately resulting in cracking of the GaN film. Low temperature AlN interlayers were found
to be effective in suppressing cracking by reducing tensile stress. The interlayer approach
permits tailoring of the film stress to optimize film structure and properties.
Nanometer-Scale Imaging of Lattice Deformation with Transmission Electron Micrograph
Authors: Takashi Ide Takashi Ide , Akira Sakai Akira Sakai , Keiji Shimizu Keiji Shimizu
Published: October 2002

We demonstrate a new method of imaging crystal lattice strain with spatial resolution on the nanometer scale. The method, Fourier transform mapping (FTM), is based on the mapping of spot positions in local Fourier-transformed images from a transmission electron microscope image. Lattice deformation caused by island formation due to strained epitaxial growth is imaged and the relief of the strain in the lateral direction, as well as that in the normal direction, is clearly visible in the lattice-deformation image.
Effects of the Dielectric Layer on a Planar and a Coplanar Discharge Breakdown
Authors: andGuangsup Cho Young-Guon Kim
Published: October 2002

There are two influences of a dielectric layer on the breakdown in Paschen's law.
The potential difference at the dielectric layer itself enhances the minimum value of firing voltage, while the
strong field in the discharge space with a large dielectric constant reduces the firing voltage in a high pressure
range. Specially in a coplanar geometry like AC-PDP [S. Sato et al. : IEEE Trans. Electron Devices 23 (1976) 328.], the firing voltage is shown to be higher
due to the non-uniformity of the electric field along with the thickness of the dielectric layer.
Effect of Fluorine Concentration on the Metal-Insulator-Semiconductor (MIS) Solar Cell Output Performance by Liquid Phase Deposition
Authors: Huang Chien-Jung , Houng Mau-Phon , Wang Yeong-Her , Wang Na-Fu , Chang Wai-Jyh
Published: October 2002

Metal-insulator-semiconductor (MIS) solar cells with the insulating layer fabricated by liquid phase deposition (LPD) method has been shown to have good output performance in various literature published. In this paper, a high quality insulating layer is developed via LPD method with the fluorine content controlled by the growth solution concentration. The addition of fluorine to enhance the solar cell efficiency is first discussed. Then an optimum fluorine content is suggested at the end of this paper. The value of the fluorine content is controlled by growth solution concentration. Solar cells with thin fluorinated oxide film reveals good performance in the illuminated characteristics. And thus novel fluorinated thin oxide film is a good candidate for the replacement of existing MIS junction I-layer.
The Role of Intermolecular Electrostatic Interaction on Appearance of the Periodic Band Structure in Type I Collagen Fibril
Authors: Itoh Takashi , Kobayashi Masahiro , Hashimoto Masato
Published: October 2002

Intermolecular electrostatic interaction between staggered tropocollagens is calculated, focussing on the condition such that D=(G+L)/K in the collagen fibril with a periodic band structure, where D, G and L are lengths of band period, gap region and tropocollagen molecule respectively, and K=[L/D]+1 where [L/D] is the highest integer below L/D. By changing D, G and K, only two cases are found where the interaction energy is minimum at every position with multiples of D; i.e., D=234, G=124, K=5 and D=235, G=129, K=5. Such results propose the origin of a periodic band structure or the Hodge-Petruska scheme and a pseudohexagonal crystal in type I collagen fibrils.
Photorefractive Optical Exclusive OR Logic Operation and Optical Images Subtraction with Incoherent Input Channels
Authors: Lee Hsiao-Yi , Yau Hon-Fai , Cheng Nai-Jen
Published: October 2002

We propose an optical device to perform the functions of an XOR (exclusive OR) logic gate. We have also presented some experimental results showing the performance of the device. The device consists of two high gain BaTiO3 crystals as its core components. The working principle of the gate is based on the phenomenon of self-pumped phase conjugation and the suppression of it by an ordinarily polarized beam. In this way, the two input channels of the system are not necessary to be coherent.
Influence of Lattice Misfit on Surface Morphology of Vanadyl-Phthalocyanine Molecular Beam Epitaxy Films Grown on KCl/KBr Mixed-Crystal Substrates
Authors: Satoru Nakao Satoru Nakao , Hajime Hoshi Hajime Hoshi , Makoto Gomyou Makoto Gomyou , Ken Ishikawa Ken Ishikawa , Hideo Takezoe Hideo Takezoe
Published: October 2002

The influence of the lattice misfit on the surface morphology and grain size of vanadyl-phthalocyanine (VOPc) epitaxial films has been investigated using KCl/KBr mixed-crystal substrates. The grain size in thick films becomes smaller as the misfit becomes larger, whereas the initial island size is large when the misfit is large. This relation in the thick films is consistent with the equilibrium theory developed for the covalent heteroepitaxial system showing isolated islands growth, as in the present case.
Quenching of Vacancies in Aluminum Interconnections on Semiconductor Devices
Authors: Aoyagi Minoru , Asada Kunihiro
Published: October 2002

The vacancy formation energy in Al–2 wt%Si interconnections on semiconductor devices with a SiN passivation layer is studied using the quenching technique. We find that the vacancy formation energy is 0.60±0.07 eV in the temperature range 200 to 300°C, while the theoretical calculation yields a value of 0.64 eV for bulk Al–2 wt%Si and 0.59 eV for the Al–2 wt%Si interconnection with a SiN passivation layer. The difference is attributed to the fact that the thermal expansion coefficient of aluminum is larger than that of SiN, so that the aluminum interconnection is strained due to the difference in the expansion. The strain enhances the generation of vacancies.
Measurement of Ion Species Utilizing Ion-Bursts in an Ar/SF 6 Mixture Plasma
Authors: Shinji Yoshimura Shinji Yoshimura , Yoshinobu Kawai Yoshinobu Kawai
Published: October 2002

Ion species in a dc discharge of Ar/SF6 gas mixture are measured by a simple method utilizing ion-bursts. In an Ar plasma, a single ion-burst is observed and the ion species, which is determined from the velocity of the ion-burst (=(2e
V/m

i
)1/2), is Ar+. On the other hand, a number of ion-bursts are observed in an Ar/SF6 mixture plasma and corresponding ion species are found to be Ar+, SF3
+ and SF5
+. The existence of SF3
+ and SF5
+ is similar to that in the RF discharge of Ar/SF6 gas mixture, which has already been reported by Sasaki et al. [S. Sasaki et al.: Jpn. J. Appl. Phys. 36 (1997) 847]. We also discuss the possibility of determination of the sheath structure from ion-bursts using the concept of multiple pseudowaves.
Etching Residues of Sputtered Ta Film Using Chlorine-Based Plasma
Authors: Iba Yoshihisa , Kumasaka Fumiaki , Takeda Masayuki , Aoyama Hajime , Yamabe Masaki
Published: October 2002

Ta films are used as X-ray mask absorbers. Spindly etching residues of the Ta film are generated on a polished SiC film when using chlorine-based plasma. We found that etching residues were generated because of microholes which exist on the polished SiC film surface, and that etching residues generally originated from the steep slope of the substrate. For the Ta film on the Si slope, a broad peak of β-Ta(410) was observed in addition to that of β-Ta(002), which is found on the Si plane. An orientation different from β-Ta(002) appears to reduce the dry etching rate. We attempted Ar sputtering of the SiC surface to smooth the slopes in the SiC microholes. Etching residues did not originate in the case of the Ta film deposition on the polished SiC film after Ar sputtering. Therefore, Ar sputtering of polished SiC is very useful for avoiding the formation of etching residues.
Electric Field-Induced Adsorption/Desorption of Oxygen on a Pd-SnO x-Si 3N 4-SiO 2-Si-Al Capacitor
Authors: Kyo Kim Chang , Poo Kang Weng , Ho Kim Young , Ihn Cho Nam
Published: October 2002

A capacitor utilizing the Pd-SnOx-Si3N4-SiO2-Si-Al structure to detect oxygen was developed. The capacitor is able to detect O2 in a vacuum environment at a much lower operating temperature than the conventional solid state gas sensors. Experimental results showed that the oxygen adsorption on the device was reduced by the application of a positive gate bias. The suppression of oxygen ions at the Pd-SnOx interface by an external positive gate bias allows us to use the Pd-SnOx-Si3N4-SiO2-Si-Al capacitor as an oxygen sensor. This suppression of oxygen is explained by a model demonstrating that the oxygen adsorption on the device could be suppressed by a downward bending of the energy band of the SnOx layer, under a relatively high positive gate bias.
Photoluminescence of a High Quality CuInSe2 Single Crystal
Authors: Chatraphorn Somphong , Yoodee Kajornyod , Songpongs Pong , Chityuttakan Chanwit , Sayavong Khampheuy , Wongmanerod Somrit , Holtz Per Olof
Published: October 2002

A CuInSe2 (CIS) bulk single crystal grown by the directional freezing method from the melt at 1250°C shows superior crystal quality, as evidenced by its (p-type) electrical properties. Photoluminescence at 1.5 K shows a strong and well resolved spectrum with fine structures never before observed from this compound. Free exciton emission exhibits a doublet structure which can either be described as a splitting due to the uniaxial crystal field or as a polariton. The energy gap of the CIS semiconductor as determined from the temperature dependence of the free exciton line is 1.058 eV. Two moderate free-to-bound transitions are assigned to VCu and CuIn acceptors. A weak PL peak corresponding to a deep level is interpreted as arising from the Sei acceptor. Strong phonon replicas are also observed for the first time in a CIS bulk single crystal. The phonon wavelength of 218–237 cm-1 is in good agreement with the reported Raman result of 233 cm-1 for the LO phonon.
Low-Temperature Selective Growth of ZnSe and ZnS on (001) GaAs Patterned with Carbonaceous Mask by Metalorganic Molecular-Beam Epitaxy
Authors: Avramescu Akio Ueta , Katsuhiro Uesugi Katsuhiro Uesugi , Ikuo Suemune Ikuo Suemune , Hideaki Machida Hideaki Machida , Norio Shimoyama Norio Shimoyama
Published: October 2002

Selective growth of ZnSe and ZnS on (001) GaAs substrates patterned with a carbonaceous mask was examined by metalorganic molecular-beam epitaxy. The minimum growth temperature to achieve selective growth of ZnSe was 400°C, while that for ZnS was the lower temperature of 300°C. These growth temperatures for selective growth are much lower than those reported up to now. The carbonaceous masks were deposited by electron-beam irradiation, and the deposition processes will be discussed in some detail. Submicron resolution with this low-temperature selective growth will be demonstrated.
Nonequilibrium Microwave Emission from DC-Biased High Tc YBa2Cu3O7-y Junctions
Authors: Lee Kiejin , Iguchi Ienari , Arie Hiroyuki , Kume Eiji
Published: October 2002

We report the observation of microwave emission from dc-biased high T
c Au/insulator/YBa2Cu3O7-y
junctions, which provides a novel method of generating broad-band microwaves. The microwave intensity is typically of the order of subpicowatts, and increases almost linearly with the increase of junction current and vanishes as the bath temperature approaches T
c. The observed effect is not similar to the Josephson effect and may be interpreted in terms of the nonequilibrium dynamics involving Cooper pairs and quasiparticles.
Structural Study on Self-Assembled Monolayers of Alkanedithiol Molecules
Authors: Kei Kobayashi Kei Kobayashi , Junzo Umemura Junzo Umemura , Toshihisa Horiuchi Toshihisa Horiuchi , Hirofumi Yamada Hirofumi Yamada , Kazumi Matsushige Kazumi Matsushige
Published: October 2002

Structures of self-assembled monolayers (SAMs) of alkanedithiol molecules were studied using an ultrahigh vacuum scanning tunneling microscope (UHV-STM) and by Fourier transform infrared reflection-absorption spectroscopy (FT-IR-RAS). Clearly resolved STM images of alkanedithiol SAMs revealed striped structures as bright lines and the distance between the adjacent bright lines was about 1.5 nm, which is in good agreement with the length of the alkanedithiol molecule. Furthermore, the intensities of the CH2 stretching bands in FT-IR-RAS measurement of alkanedithiol SAMs were stronger than those of alkanethiol SAMs. We suggest that the molecules in alkanedithiol SAMs are arranged with their axes parallel to the gold substrate.
A Novel Alignment Process in Liquid Crystal Cell Fabrication Using Reversible Poly(Vinyl–Cinnamate) Photoalignment Technique
Authors: Rumiko Yamaguchi Rumiko Yamaguchi , Akira Sato Akira Sato , Susumu Sato Susumu Sato
Published: October 2002

We propose a novel process to make liquid crystal (LC) cells using a poly(vinyl–cinnamate) photoalignment technique. In this process, the photoaligning treatment is performed after the LC cell is assembled. The LC aligns homogeneously on both substrates upon a single shot of linearly polarized UV irradiation at the temperature above the nematic–isotropic transition temperature. In addition, several repetitions of photoaddressing and –erasing can be demonstrated in this LC cell. This reversible alignment is discussed in relation to the slow–axis direction of the photoalignment film.
New Electrodeless Light Source Intensified by Electron Cyclotron Resonance Heating
Authors: Rui Zhang Rui Zhang , Masato Kanno Masato Kanno , Yasushi Nishida Yasushi Nishida , Noboru Yugami Noboru Yugami
Published: October 2002

Brighter and electrodeless light sources are developed by introducing the electron cyclotron resonance (ECR) effect into the discharge area. In the present proof-of-principle demonstration, a microwave source with a frequency of 2.45 GHz, and a maximum power of 1 kW is used. A mercury lamp placed inside the microwave cavity is immersed in a uniform magnetic field, B. At B = 875 G, which satisfies the ECR condition, the light intensity is increased by 28% at an incident microwave power of 800 W. Short-wavelength components are effectively improved relative to long ones.
Highly Soluble Anthraquinone Dyes with CF3-Groups for Guest-Host Liquid Crystal Displays
Authors: Iwanaga Hiroki , Naito Katsuyuki
Published: October 2002

Anthraquinone dyes possessing thiophenyl substituents with a trifluoromethyl (CF3)-group at the meta position were synthesized for the first time. Among these dyes, only asymmetrical compounds were highly soluble in fluorinated liquid crystals even at low temperatures, and their solubilities were higher than the corresponding non-CF3-substituted ones.
Design and Characterization of High-Torque/Low-Speed Silicon Based Electrostatic Micromotors Using Stator/Rotor Contact Interactions
Authors: Minotti Patrice , Langlet Philippe , Bourbon Gilles , Masuzawa Takahisa
Published: October 2002

Capabilities of future direct-drive electrostatic actuators are investigated through the mechanical characterization of annular-type polysilicon micromotors. Contact interactions are provided at the stator/rotor interface in order to allow high integrated speed reduction to be performed. The driving torque is therefore considerably amplified, as a consequence of the torque/speed duality. Direct torque measurements are performed through a self-adjustable torque sensor that is integrated in the polysilicon rotor. The first experimental results presented here give rise to the expectations of numerous direct drive applications down to the micrometer scale.
Determination of Cavity Loss in Proton Implanted Vertical-Cavity Surface-Emitting Lasers
Authors: Ha Kyoung-Ho , Lee Yong-Hee
Published: October 2002

The cavity loss and the threshold gain of the proton implanted 780-nm vertical-cavity surface-emitting laser(VCSEL)s are determined by varying the mirror loss with optical feedback. Taking the nonlinear gain effect into account, the total internal loss of αt = 68 cm-1 and the threshold modal gain of g
th = 89 cm-1 are obtained in a gain guided VCSEL whose diameter is 15 µm. This method can handle the cases of large optical feedback or large threshold gain where the nonlinear gain effect becomes significant. Unlike the other methods, our approach works well for gain-guided lasers where thermal effect generates unreliable values of differential quantum efficiency.
Internal Electron Emission in Phosphorus-Doped Polycrystalline Diamond Field Emitters
Authors: Sugino Takashi , Kuriyama Kenji , Kawasaki Seiji , Iwasaki Yukio , Shirafuji Junji
Published: October 2002

Temperature dependence of a field emission characteristics is investigated for a phosphorus(P)-doped polycrystalline diamond film as compared with that of an undoped one. The threshold voltage decreases with increasing temperature for a P-doped diamond film, while no variation in the threshold voltage occurs for an undoped diamond film. An increase in the ionized donor concentration with increasing temperature leads to a reduction in the tunnel barrier width at the interface between the diamond and the cathode, resulting in an enhancement of the emission current. This suggests that the internal electron emission determines the field emission characteristics. A reduction in the threshold voltage with increasing P-doping concentration can also be understood to be due to internal electron emission. Field emission characteristics in the higher voltage region features a space charge limited current.
Reduced Cracking in Melt-Grown RBa 2Cu 3O 7 (R=Nd, Sm)/Gold Composites
Authors: Wu Nae-Lih , Hsu Cheng-Che , Lee Che-Hao
Published: October 2002

Melt-grown (MG) RBa2Cu3O7 (R-123; R=Nd, Sm) containing uniformly distributed Au particulate inclusions have been prepared by slow cooling at oxygen pressures between 2 and 152 Torr (air), where Au is engulfed into the oxide grains as melt droplets. Au does not show adverse effect on either T
c or the nucleation and growth behaviors of the R-123 oxides. On the other hand, the presence of Au inclusions in the solidified R-123 oxide matrices greatly reduces cracking and has led to enhancement in the supercurrent loop size perpendicular to the basal plane. Controlled mechanical testing also shows that the Au inclusions are effective in blunting crack tip and changing its propagation path.
Field Emission Characteristics from Grains and Polycrystalline Films of Phosphorus-Doped Diamond Grown by Chemical Vapor Deposition
Authors: Yokota Yuuko , Kawasaki Seiji , Sugino Takashi
Published: October 2002

Polycrystalline diamond films are prepared on Si substrates with various growth times by means of hot-filament chemical vapor deposition. Phosphorus atoms are doped as donor impurities. Field emission characteristics of diamond films are measured. Neither the film thickness nor the surface roughness has any influence on the field emission characteristics. The experimental results suggest internal electron emission from the Si substrate into the conduction band of the diamond. Moreover, it is found that the electron emission from diamond grains occurs at a lower electric field in comparison with that from diamond films.
Step-Flow Metalorganic Vapor Phase Epitaxy of GaN on SiC Substrates
Authors: Nishida Toshio , Akasaka Tetsuya , Kobayashi Naoki
Published: October 2002

Metalorganic Vapor Phase Epitaxy (MOVPE) growth of GaN on SiC substrates is dominated by the step-flow growth mode within a 10 µm2 area. Compared to the growth on sapphire substrates, there is no spiral growth originating from screw dislocations and two dimensional islands within the 10 µm2 area, showing that the step-flow growth mode is dominant. The surface mostly consists of 140-nm-wide atomic terraces and doubly stacked monolayers (DSM) corresponding to a unit cell height. This coupling of DSM dissolves into a pair of monolayer steps at the adjacent DSM steps forming a twilled step (TWS) structure, due to the asymmetry between these two layers in a GaN unit cell.
Amber InGaN-Based Light-Emitting Diodes Operable at High Ambient Temperatures
Authors: Mukai Takashi , Narimatsu Hiroki , Nakamura Shuji
Published: October 2002

High-efficiency amber InGaN single-quantum-well (SQW) structure light-emitting
diodes (LEDs) with a luminous efficiency of 10 lm/W were developed. At a
current of 20 mA, the external quantum efficiency, the output power and the emission
wavelength of the amber InGaN SQW structure LEDs were 3.3%, 1.4 mW and 594 nm,
respectively. The output power of InGaN LEDs was about twice as high as that of
AlInGaP LEDs. There was a large difference in the temperature dependence of the
output power between InGaN and AlInGaP LEDs. When the ambient temperature was
increased from room temperature to 80°C, the output power of AlInGaP LEDs
decreased dramatically. On the other hand, the output power of the InGaN LEDs
remained almost constant.
Numerical Analysis of Synchronous Switching in Double-Barrier Josephson Junctions
Authors: Hirotake Yamamori Hirotake Yamamori , Tsuneo Kikuchi Tsuneo Kikuchi , Satoshi Kohjiro Satoshi Kohjiro , Akira Shoji Akira Shoji
Published: October 2002

The mechanism of synchronous switching in double-barrier Josephson junctions has been analyzed by means of numerical calculations.
It is found that an interaction of the screening current between electrodes of double-barrier junctions cannot be ignored if the common electrode is thinner than the magnetic penetration depth and that the synchronous switching occurs when the junction size is larger than the Josephson penetration depth.
Multiple Beam Coupling Using a Novel Barium Titanate Mutually-Pumped Phase Conjugator
Authors: Chang Chi Ching
Published: October 2002

A novel two-fish-head configuration of a mutually-pumped phase conjugator for
multiple beam coupling is demonstrated in a photorefractive barium titanate crystal.
The ability of the phase conjugator to effectively and simultaneously create three phase-conjugate replicas without cross talk is also presented. The tolerance of the coupling
efficiency to positional misalignment is assessed as well.
On Antiferroelectric Smectics Exhibiting Successive Phase Transitions in the Electric Field
Authors: Yamashita Mamoru , Tanaka Satoshi
Published: October 2002

The phase diagram of the axial next nearest neighbour Ising model with the third nearest
neighbour interaction in an electric filed is obtained to study the phase transitions occurring in
antiferroelectric smectic liquid crystals. Under suitable conditions, the jumps of the order
parameters are small, though the transitions are necessarily of the first order in the absence of the
electric field. The instability line of the ferroelectric phase, showing instability of the uniform
phase with respect to periodic perturbation is also tested. The phase diagrams strongly suggest
that the structure of the intermediate ferrielectric phase FIH has the wave number 2/7, and are also
consistent with the previous result on FIL.
Molecular Orbital Study of the Adsorption of Chloroaluminum Phthalocyanine on a NaCl (100) Surface
Authors: Hoshi Hajime , Nakao Satoru , Ishikawa Ken , Takezoe Hideo
Published: October 2002

An ab-initio molecular orbital method has been applied to
study the adsorption site of chloroaluminum phthalocyanine on
the NaCl (100) surface. The most stable adsorption site was found
in the geometry where the aluminum, four aza-bridging nitrogens,
and four phenyl rings of chloroaluminum phthalocyanine are
located on Na cations, which supports the model proposed by
previous molecular mechanics calculations.
Acoustic Emission in Damaged Ferroelectric Lead Zirconate Titanate Ceramics
Authors: Aburatani Hideaki , Uchino Kenji
Published: October 2002

Field induced acoustic emissions (AE) in damaged ferroelectric ceramics have been studied.
The field induced AE was not observed after the poling was completed at given electric fields.
However, new AE was generated when the samples were damaged. It has been demonstrated
that the AE method can be used to detect the damage of piezoelectric/ferroelectric materials and to
determine safe driving electric fields.
X-ray Fluorescence Analysis of Rare-Earth Atoms in Materials by Use of Ultrashort Wavelength X-rays
Authors: Takahashi Yasuhiko , Yamamoto Kazuki , Ohshima Ken-ichi , Yukino Ken , Okamura Fujio P.
Published: October 2002

A new technique of X-ray fluorescence analysis using ultrashort-wavelength X-rays was tested
to obtain the K-series of spectra for rare-earth elements in two different kinds of materials, i.e. powder
samples of rare-earth oxides and single crystals of rare-earth hexaborides. This technique
utilizes a solid-state detector and multichannel pulse-height analyzer, and satisfies the
requirements for quantitative identification in samples containing heavy elements. This technique
was applied to determine the composition of the mixed compound La1-x
Ce
x
B6 (x=0.25, 0.50 and
0.75). There is good agreement, within the limits of experimental error, between the values thus
obtained and the nominal values.
Influence of As Autodoping from GaAs Substrates on Thick Cubic GaN Growth by Halide Vapor Phase Epitaxy
Authors: Harutoshi Tsuchiya Harutoshi Tsuchiya , Kenji Sunaba Kenji Sunaba , Masato Minami Masato Minami , Takashi Suemasu Takashi Suemasu , Fumio Hasegawa Fumio Hasegawa
Published: October 2002

GaN layers were grown on (001) GaAs substrates by halide vapor phase epitaxy (HVPE) on either a high-quality cubic buffer layer grown by metalorganic molecular beam epitaxy (MOMBE) or a HVPE buffer layer on both sides of the substrate.
Though a high-quality cubic GaN (cubic component : more than 99% for 2µm thick layer) was grown on the MOMBE buffer layer, the photoluminescence intensity was less than that of the layer grown on the HVPE buffer layer by about two orders of magnitude.
This was found to be due to arsenic (As) autodoping from the back side of the GaAs substrate.
The As autodoping decreased the optimum growth temperature of cubic GaN by about 50°C.
The hexagonal component increased with an increase in the growth thickness, independent of the initial cubic purity of the grown layer, suggesting that influence of the As autodoping decreased with an increase in the growth thickness.
Effect of Residual Water on Giant Magnetoresistance in Co/Cu Superlattices
Authors: Takahiro Shiga Takahiro Shiga , Motofumi Suzuki Motofumi Suzuki , Koichi Mukasa Koichi Mukasa , Yasunori Taga Yasunori Taga
Published: October 2002

We have studied the effects of
residual water during the deposition process
and the deposition rate
on the giant magnetoresistance (GMR) in Co/Cu superlattices
prepared by sputtering.
The magnetoresistance (MR) ratio decreases drastically
with an increase in the amount of residual water
and a decrease in the deposition rate.
In order to understand these results,
we introduce the residual water to deposition rate ratio parameter, ξ,
which is proportional to the exposure of the surface of the sample
to residual water.
It has been found that the MR and magnetic properties of the superlattices are
universally expressed in terms of ξ.
Multi-Domain Homeotropic Liquid Crystal Display Based on Ridge and Fringe Field Structure
Authors: Lien Shui-Chih A. , Cai Chen , Nunes Ronald W. , John Richard A. , Galligan Eileen A. , Colgan Evan , Wilson John S.
Published: October 2002

A ridge and fringe field multi-domain homeotropic (RFFMH) liquid crystal display was
demonstrated. The operating principle of this new display mode is the combination effect of a
fringe field and ridge structure to control the tilt direction of the liquid crystal molecules when a
voltage is applied. No rubbing treatment is required and, with proper compensation films, the
display has very wide viewing angles.
Surface Protrusions of Chemical Vapor Deposited TiN Films Caused by Cu Contamination of Silicon Substrates
Authors: Cheng Degang , Ogawa Yoshifumi , Hamamura Hirotaka , Shirakawa Hiroaki , Osawa Toshio , Takami Seiichi , Komiyama Hiroshi
Published: October 2002

We found that surface protrusions of chemical vapor deposited TiN films are caused by
reactions between copper contaminants and the silicon substrate. Depending on the size of
the copper contaminant, two kinds of defects were formed: copper silicide (CuSi) and
silicon dioxide. The silicon dioxide is formed because of the catalytic role of copper
silicide. The defects grow both into and out of the silicon substrate. In the formation of
copper silicide and silicon dioxide, copper, silicon, and oxygen are the major participating
species.
The Effect of an Electrode on Plasma Potential Dip in RIKEN 18 GHz Electron Cyclotron Resonance Ion Source
Authors: Nakagawa Takahide , Biri Sandor , Kidera Masanori , Miyazawa Yoshitoshi , Hemmi Masatake , Chiba Toshiya , Inabe Naohito , Kase Masayuki , Kageyama Tadashi , Kamigaito Osamu , Goto Akira , Yano Yasushige
Published: October 2002

We measured the beam intensity of argon ions as a function of
negative bias voltage of an electrode under the pulsed mode operation. We
observed that the potential dip becomes deeper by increasing negative bias
voltage. We concluded that the electrode works to optimize the plasma
potential and helps to increase the beam intensity of highly charged argon ions.
Violet InGaN/GaN/AlGaN-Based Laser Diodes with an Output Power of 420 mW
Authors: Nakamura Shuji , Senoh Masayuki , Nagahama Shin-ichi , Iwasa Naruhito , Yamada Takao , Matsushita Toshio , Kiyoku Hiroyuki , Sugimoto Yasunobu , Kozaki Tokuya , Umemoto Hitoshi , Sano Masahiko , Chocho Kazuyuki
Published: October 2002

The InGaN multiquantum-well-structure laser diode (LD) was grown on epitaxially laterally
overgrown GaN on sapphire. The LDs with cleaved mirror facets showed an output
power as high as 420 mW per facet under room temperature continuous-wave (CW) operation.
The fundamental transverse mode was observed up to an output power of 100 mW. The lifetime
of the LDs at a constant output power of 30 mW was longer than 160 h under CW operation at
an ambient temperature of 50°C. The wavelength drift caused by the temperature change was
estimated to be 0.06 nm/K, while that of the red AlInGaP LDs was 0.3 nm/K.
Sidelobe-Suppression of Grating-Assisted Codirectional Coupler Filter by Selective Area Growth
Authors: Park Chan-Yong , Kim Dug-Bong , Lee Seung-Won , Kim Jeong-Soo , Oh Kwang-Ryong , Kim Hong-Man , Yoon Tae-Hoon , Pyun Kwang-Eui
Published: October 2002

We propose and demonstrate a technique for the sidelobe suppression in an
InP/InGaAsP semiconductor grating-assisted codirectional coupler (GACC) optical filter.
By employing selective area growth (SAG) in an InP separation layer, the epitaxial film
thickness was spatially controlled so that the coupling coefficient distribution between
two waveguides has the Hamming functional form. Most sidelobes are suppressed below
-12 dB, which is low compared to the conventional GACC filters.
Liquid Phase Chemical-Enhanced Oxidation for GaAs Operated Near Room Temperature
Authors: Hwei-Heng Wang Hwei-Heng Wang , Chien-Jung Huang Chien-Jung Huang , Yeong-Her Wang Yeong-Her Wang , Mau-Phon Houng Mau-Phon Houng
Published: October 2002

A new chemical enhanced oxidation method for gallium arsenide (GaAs) in liquid phase near room temperature (40°C–70°C) is proposed and investigated. Featureless oxide layers with good uniformity and reliability can be grown efficiently on GaAs without any extra energy source. A relatively high oxidation rate (≃1000 Å/h), about 50 times higher than that obtained during oxidation in boiling water has been realized. Based on the results of X-ray photoelectron spectroscopy (XPS), excellent chemical stability after thermal annealing as well as good chemical stoichiometry have been realized. The oxide was determined to be composed of Ga2O3 and As2O3.
Identification of Surface Atoms of LiGaO2(001) Substrate for Hexagonal GaN Film by Coaxial Impact Collision Ion Scattering Spectroscopy
Authors: Ishii Takao , Mukaida Masashi , Nishihara Takaharu , Hayashi Shigeki , Shinohara Makoto
Published: October 2002

Terminating surface atoms of LiGaO2(001) substrate for GaN thin film growth have been directly identified by coaxial impact collision ion scattering spectroscopy (CAICISS). We found that the terminating atoms of
the easily etched surface of the substrate are oxygen and that those of the
hardly etched surface are metal (Li and Ga). The relation is explained by
the surface bonding model of the wurtzite-type AII-BIV compound. GaN thin films grew epitaxially only on the metal surface of the substrate.
The Improvement of Liquid Phase Deposition of Silicon Dioxide with Hydrochloric Acid Incorporation
Authors: Lee Ming-Kwei , Lin Ching-Hsing , Yang Ching-Nan , Yang Chi-Da
Published: October 2002

Liquid phase deposition of silicon dioxide (LPD-SiO2) provides the advantages of
room temperature growth, good step coverage and selective growth, and has high
potential in integrated circuit fabrications. In this paper, a simple method to improve the
quality of LPD-SiO2 was developed with the incorporation of hydrochloric acid (HCl)
which can enhance the deposition rate of LPD-SiO2. From the current-voltage and
capacitance-voltage characteristics, the flat-band voltage and leakage current were
improved by HCl incorporation into LPD-SiO2 films.
Langevin Type Alignment in a Smectic Liquid Crystal Mixture Showing V-Shaped Switching As Studied by Optical Second-Harmonic Generation
Authors: San-Seong Seomun San-Seong Seomun , Byoungchoo Park Byoungchoo Park , A. D. L. Chandani A. D. L. Chandani , David S. Hermann David S. Hermann , Yoichi Takanishi Yoichi Takanishi , Ken Ishikawa Ken Ishikawa , Hideo Takezoe Hideo Takezoe , Atsuo Fukuda Atsuo Fukuda
Published: October 2002

Second-harmonic generation (SHG) was observed in a
homogeneously aligned smectic C*-like liquid crystal
(LC) cell showing V-shaped switching during the
application of a triangular wave. At normal
incidence of light, abnormally strong SHG signals were
observed at about zero electric field. It was confirmed
that this phenomenon is characteristic in LCs showing
the V-shaped switching, and is not observable in typical
ferroelectric and antiferroelectric LCs. The dynamic
response of SHG was successfully simulated using the
two-dimensional Langevin type potential model.
Structural Dependence of GaN/Al2O3 on Electric Bias During Electron-Cyclotron-Resonance Plasma-Excited Molecular Beam Epitaxy (ECR-MBE)
Authors: Shimizu Yuui , Tominari Tatsuya , Hokuto Shingo , Chiba Yasuo , Nanishi Yasushi
Published: October 2002

GaN crystals were grown on a (0001) sapphire substrate by electron cyclotron resonance plasma excited molecular beam epitaxy (ECR-MBE). Grown crystals were analyzed by photoluminescence (PL) measurement at low temperatures and by pole figure
mode X-ray diffraction (XRD) mapping. The GaN crystal structure changed from hexagonal dominant to cubic dominant as the V/III ratio decreased. It was also observed for the first time that a similar structural
change occurred upon the application of a bias voltage to the substrate. This structural change was considered to be induced by the change in the effective V/III ratio on the growing surface introduced by the
positive bias. These results imply the possibility of growing hexagonal and cubic heterostructures and supperlattices by simply changing the bias voltage during growth.
Flux Coupling in the Direct-Coupled High-Tc Superconducting Quantum Interference Devices
Authors: Maruyama Emi , Kuriki Shinya , Yokosawa Kouichi , Sha Ahmad Rashdi , Suzuki Daisuke , Koyanagi Masao
Published: October 2002

We have fabricated high-T
c dc superconducting quantum interference devices (SQUIDs), which have different geometries of the hole and configurations of
current injection leads, in the direct-coupling magnetometer, and measured the coupling efficiency of the flux generated by the injected current. It has been found that the coupling is efficient in the case
where the current flows uniformly across the width of the path around the SQUID hole. High coupling of more than 80% was obtained in a geometry of narrow parallel strips with wide slit of the SQUID hole between them.
Observation of Self-Channeled Plasma Formation and Bulk Modification in Optical Fibers Using High-Intensity Femtosecond Laser
Authors: Cho Sung-Hak , Kumagai Hiroshi , Yokota Isao , Midorikawa Katsumi , Obara Minoru
Published: October 2002

We report the first experimental observation of laser-induced self-channeled plasma formation and bulk modification in multimode optical fibers during excitation
by a high-intensity (more than 1011 W/cm2) femtosecond (110 fs) Ti: sapphire laser (780 nm). Solid-density plasma formation at various input intensities and the corresponding variation of anti-Stokes
spectra were observed simultaneously. The threshold intensity for plasma formation in the optical fiber was found to be 8×1011 W/cm2. When the input intensity reached 1.5×1012 W/cm2, self-channeled plasma formation was observed
at a distance of 9–10 mm from the input end of an optical fiber. After 5 min of irradiation at 1.7×1012 W/cm2, bulk modification, 5 µm in diameter and approximately 6 mm in length was observered in
two types of multimode optical fibers with core/cladding diameters of 100/110 µm and 200/220 µm.
High-Mobility Two-Dimensional Electron Gas in an Undoped Heterostructure: Mobility Enhancement after Illumination
Authors: Tadashi Saku Tadashi Saku , Koji Muraki Koji Muraki , Yoshiro Hirayama Yoshiro Hirayama
Published: October 2002

High-mobility two-dimensional electron gas (2DEG) is formed at an undoped
GaAs/AlGaAs inverted heterointerface through the field-effect using a back-gate.
Despite the structure being undoped, mobility enhancement is observed
at 1.6 K after illumination. This suggests effective reduction
of background impurity scattering by illumination. The maximum mobility
reached after illumination, 5×106cm2/V·s,
is the highest value ever reported for gated undoped
heterostructures,
including both normal- and inverted-type structures.
This mobility is also the
highest ever
reported for inverted GaAs/AlGaAs heterostructures.
Shrinkage of Grown-in Defects in Czochralski Silicon During Thermal Annealing in Vacuum
Authors: Ueki Takemi , Itsumi Manabu , Takeda Tadao , Yoshida Kiyokazu , Takaoka Akio , Nakajima Sigeru
Published: October 2002

We examined the effect of thermal annealing in vacuum on the behavior of dual-type
octahedral void defects in Czochralski silicon. We found that the smaller void shrinks first at
about 1100°C and that during the shrinkage of the smaller void to extinction, the bigger void
maintains its structure and size. In addition, we found that shrinkage of the smaller void
begins from the adjacent region between the two voids. We believe that the effect of
minimizing the surface energy first takes place selectively in the smaller void and that after
the extinction of the smaller void, the effect of minimizing the surface energy takes place in
the bigger void.
Experimental Studies on the Pulse Compression Characteristics of an Additive-Pulse Mode-Locked CW Nd:YLF Laser
Authors: Joon Ahn Seung , Weon Kwak Ho
Published: October 2002

Additive-pulse mode-locking (APM) using a nonlinear external cavity was
performed with a cw Nd:YLF laser at a wavelength of 1.053 µm.
The APM pulsewidth of 4.5 ps at a repitition rate of 100 MHz has been
obtained. This APM pulse was compressed using a fiber-grating
pair for various grating separations. For optimum grating separation,
we obtained a pulse as short as 210 fs.
Enhanced Emission from Europium Complex Utilizing Quantum-Well Structure in Organic Electroluminescent Device
Authors: Hamada Yutaka Ohmori , Katsumi Yoshino Katsumi Yoshino
Published: October 2002

Enhanced electroluminescence from europium (Eu) complex has been observed utilizing single, or multiple quantum–well structures consisting of a Eu complex well layer sandwiched between azomethin–zinc complex layers. Sharp emission at 614 nm has been observed from the Eu complex in the quantum-well structure. The thinner the well layer of the Eu complex, the stronger the emission intensity from it, under the same injection current. The mechanism of enhanced emission from the quantum-well structure has been discussed.
Charge Transport Property in the Lyotropic Liquid Crystalline Cell Composed of Carbazolyl Groups Pendant Poly(glutamate)
Authors: Manabu Yoshida Manabu Yoshida , Shinji Mitsui Shinji Mitsui , Masanori Nagoshi Masanori Nagoshi , Norihisa Kobayashi Norihisa Kobayashi , Ryo Hirohashi Ryo Hirohashi
Published: October 2002

Polypeptide having carbazolyl groups (poly-γ-[2-(9-carbazolyl) ethyl]-L-glutamate) (PCLG) was
synthesized in order to prepare a lyotropic liquid crystalline cell with higher mobility. Typical
Time-Of-Flight (TOF) method was employed to analyze its charge transport property. Transient
photocurrent for the liquid crystalline cell showed nondispersive transport property. Relatively high
drift mobility of ca.10-3 (cm2/V·s) was obtained in the cell composed of PCLG with both intra and
interchain ordered structure.
Analysis of Heteroepitaxial AlGaAs/Si Tandem Solar Cell for Concentrator Applications
Authors: Yang Ming-Ju , Yang Jia-Lin , Yamaguchi Masafumi
Published: October 2002

The development of monolithic AlGaAs/Si tandem solar cells
for concentration applications is proposed. The theoretical
analysis is carried out to express the device parameters as a
function of the doping concentration and the dislocation
density. From the results of this theoretical analysis, it is
demonstrated that when the dislocation density is reduced to
below 104 cm-2, photocurrent matching between the top cell and
the bottom cell can be satisfied at the Al composition of Al
x
Ga1-x
As x=0.21, and the efficiency of the AlGaAs top cell increases
rapidly in the 1–100 sun concentration region. In order to
achieve very high efficiency, the dislocation density must be
reduced to below 5×105 cm-2 and concentration ratios greater than
100 times must be used.
Superconducting Properties and Microstructures of Pb-Doped Bi2Sr2Ca1Cu2Ox Spherical Particles Prepared by Containerless Solidification and Annealing
Authors: Hishinuma Yoshimitsu , Fujii Hiroki , Matsumoto Akiyoshi , Hirata Kazuto , Takeya Hiroyuki , Kumakura Hiroaki , Togano Kazumasa
Published: October 2002

The superconducting properties and microstructures of Pb-doped Bi-2212 spherical
particles prepared by containerless solidification and subsequent annealing were
investigated. After solidification, the spherical particles are present in an amorphous
state which can be transformed into the Bi-2212 phase by annealing at temperatures
above 800°C. The Pb-doped spherical particles show an improved flux pinning
behavior which is considered to arise from the modification of the modulation
structure.
Violet InGaN/GaN Light Emitting Diodes Grown by Molecular Beam Epitaxy Using NH3
Authors: Grandjean Nicolas , Massies Jean , Leroux Mathieu , Lorenzini Philippe
Published: October 2002

GaN and InGaN alloys were grown on c-plane sapphire substrates
by molecular beam epitaxy using NH3. This allows realizing light emitting
diodes (LEDs) based on InGaN/GaN single heterostructures. The forward
voltage is 3.6 V at 20 mA. The room temperature electroluminescence
exhibits a strong emission at 405 nm. The I–V characteristics were studied
as a function of the temperature. A tunneling process in the transport
mechanism is observed as for metal-organic chemical vapor deposition grown LEDs.