bluuebunny/crossref_metadata_2025_split huggingface dataset:
Property of Supercurrent Flowing through Superconducting Single-Electron Transistors with Weak Charging Effect
Authors: Hiroshi Okamoto Hiroshi Okamoto , Koichi Shimizu Koichi Shimizu , Yuichi Okuda Yuichi Okuda 
Published: October 2002

The experimental characteristics of superconducting single-electron transistors consisting of Al/Al

x

O

y

/Al tunnel junctions at ∼60 mK are presented. The single-electron charging energy E
C of our devices is small in comparison with the superconducting gap energy of 170 µeV. It is revealed that the 2e gate-charge periodic supercurrent flows at a finite voltage. We also observe that the leakage of quasi particles into the island electrode occurs.
Large Transmittance Changes Induced in Ga-Doped ZnO Thin Films Prepared by Pulsed Laser Deposition
Authors: Tanaka Akio Suzuki , Takanori Aoki Takanori Aoki , Masahiro Okuda Masahiro Okuda 
Published: October 2002

Thin films of ZnO:Ga (GZO) have been deposited on glass substrates at room temperature by a pulsed laser deposition technique using a Nd:YAG laser (λ=1064 nm). The 100-nm-thick GZO films grown in vacuum were dark brown and showed optical transmittance of less than 20% in the 300–3200 nm wavelength region. On the other hand, it was found that GZO films grown in vacuum and annealed at 400–420°C for 3–5 min showed an average transmittance of above 80% in the 400–3200 nm wavelength region. GZO films with large transmittance changes in the 400–600 nm wavelength region can be applied to high-density optical recording films.
Fluoridation of GaAs Surface in a Remote SF 6 Plasma
Authors: Kwang-Ho Kim Kwang-Ho Kim , Kyung-Soo Suh Kyung-Soo Suh 
Published: October 2002

Gallium fluoride films were directly grown on gallium arsenide (GaAs) at temperatures below	300°C	using	a radio frequency (RF) remote SF6 plasma.The growth kinetics are exhibited a rapid	initial increase for 60 minutes,	with	no significant increase thereafter. Rutherford backscattering spectrometry (RBS) and secondary	ion mass spectrometry (SIMS) showed that the GaF3 films had almost stoichiometric	composition. The	as-grown films exhibit	a current	density	of	less	than 1 µA/cm2 at a breakdown field of 1 MV/cm	and a refractive index of 2.0–2.3 at a wavelength	of 632.8 nm. A	typical value of the dielectric constant is about 5.5 as derived	from 1 MHz capacitance-voltage ( C-V) measurements. The minimum interface state density is estimated to be around 1 × 1012 cm-2·eV.
Analysis of Si–H, Si–O–H and Si–O–O–H Defects in SiO 2 Thin Film by Molecular Orbital Method
Authors: Takeshi Kanashima Takeshi Kanashima , Masanori Okuyama Masanori Okuyama , Yoshihiro Hamakawa Yoshihiro Hamakawa 
Published: October 2002

Energy states of hydrogen-related defects in SiO2 such as Si–H, Si–O–H and Si–O–O–H have been studied by theoretical analysis using molecular orbital (MO) calculation. The theoretical analyses have been carried out using both the semiempirical and ab-initio MO methods, and the ab-initio MO calculation results shows that the transition energy from the excited-singlet state to the ground state is 3.89 eV in a Si–O–O–H cluster. This value is close to that of the photoluminescence peak energy measured in the SiO2 film grown by photo-induced chemical vapor deposition. The strengths of the hydrogen bonds with Si and Si–O have been investigated, and it was found that Si–OH is more stable than Si–H.
Theoretical Study of Silicon Adatom Transfer from the Silicon Surface in Scanning Tunneling Microscopy
Authors: Nobuhiko Kobayashi Nobuhiko Kobayashi , Kenji Hirose Kenji Hirose , Masaru Tsukada Masaru Tsukada 
Published: October 2002

We have investigated the electronic structures of a silicon adatom displaced from a silicon surface with the tip of a scanning tunneling microscope using the recursion-transfer-matrix method. This method is an effective means of calculation for electronic states of a bielectrode system under electric field and current. The adiabatic potential surfaces of the adatom moving from the surface to the tip and the corresponding induced electron density distributions are presented for several values of bias voltage. A decrease in the activation barrier height is seen for both positive and negative bias cases when the tip-surface distance is 11 bohrs, while a monotonous decrease is seen only for the positive bias case at a tip-surface distance of 8 bohrs.
Magnetic Field-Induced Effects on the Melting Temperatures of Polymer Gels
Authors: Yoichiro Matsumoto Yoichiro Matsumoto , Isao Yamamoto Isao Yamamoto , Masuhiro Yamaguchi Masuhiro Yamaguchi , Yoshihiro Shimazu Yoshihiro Shimazu , Fumihiro Ishikawa Fumihiro Ishikawa 
Published: October 2002

The gel-melting temperature was observed for aqueous agarose and aqueous methyl cellulose gels which were prepared under the influence of magnetic fields up to 5 T. The exposure to magnetic fields during gelation caused the melting temperature to increase in the agarose gels (+1.0 K for the 0.2 wt% gel) and to decrease in methyl cellulose gels (-3.5 K for the 0.4 wt% gel). The change in melting temperature was reduced with increasing polymer concentration and was saturated in magnetic fields below 3 T. Stable gel structures were constructed due to the exposure to magnetic fields.
X-Ray and Photoluminescence Characterization of a Strain-Free GaAs-on-Si Structure Formed by Annealing under Ultrahigh Pressure
Authors: Takehito Jimbo Takehito Jimbo , Hiroshi Ishiwara Hiroshi Ishiwara 
Published: October 2002

Characteristics of strain-free GaAs-on-Si structures formed by annealing under ultrahigh pressure were investigated by X-ray diffraction (XRD) analysis and photoluminescence (PL) measurement. It was found that a strain-free GaAs film was formed on a Si substrate without serious degradation of the optical and crystallographical properties of the film. It was also found that no additional strain or defects were generated during PL measurement at 77 K. Next, the strain-free GaAs-on-Si structure was reannealed at atmospheric pressure, and variation of the strain was investigated. It was found in this experiment that the strain in the GaAs film increased rapidly in the first 5 min of reannealing but within 20 to 30 min it reached to a constant value which was determined by the reannealing temperature. Finally, both XRD and PL data were compared and an intensity result on the depth distribution of strain in a GaAs film was derived.
Low-Frequency Sound Source with Dual Bending Radiation Surfaces
Authors: Mitsuru Yamamoto Mitsuru Yamamoto , Hiroshi Ishimura Hiroshi Ishimura , Yoshinori Hama Yoshinori Hama , Takeshi Inoue Takeshi Inoue 
Published: October 2002

A disk bender sound source with dual radiation surfaces is designed based on the finite element method (FEM) analysis and an equivalent circuit analysis. The results of these analyses results exhibit that the sound source has a low-frequency and high-power radiation capacity and is capable of operating at ten times the normal atmospheric outer water pressure. The sound source comprises of two bending resonators. Each resonator consists of a metal disk and many piezoelectric ceramic segments. Each ceramic segment is firmly bonded to a depression on the metal disk with an epoxy resin adhesive. The sound source has external dimensions of about 80 cm diameter, 9 cm thickness and weighs 130 kg. The resonant frequency obtained is 115 Hz at a depth of 50 m, and the maximum sound pressure level successfully achieved is more than 200 dB re 1 µPa at 1 m. For the purpose of using the sound source at great depths, a pressure-compensation method, in which the inner cavity of the sound source is filled with compressed gas, is theoretically investigated.
Electronic State Distributions of He(ns, np, nd) Rydberg States Produced from Three-Body Collisional Radiative Recombination of He+ in a Helium Flowing Afterglow
Authors: Masaharu Tsuji Masaharu Tsuji , Masafumi Nakamura Masafumi Nakamura , Erika Oda Erika Oda , Masahiro Hisano Masahiro Hisano , Yukio Nishimura Yukio Nishimura 
Published: October 2002

Singlet and triplet ns, np, and nd Rydberg states of He* in the 22.72–24.53 eV range have been produced in a helium flowing afterglow. The highest excited levels in each Rydberg state increased from n=6 to 16 with an increase in the degeneracy of the upper state. The dependence of the emission intensity of He* on the He pressure and the electron density indicated that these He* states were formed by the He+/2e- three-body collisional radiative recombination reaction. The electronic state distributions, which were independent of He pressure in the range of 1.0–2.7 Torr, increased with decreasing excitation energy of He*. They were expressed by double Boltzmann distributions with effective electronic temperatures of 0.46 eV in the 22.7–24.4 eV range and 0.089 eV in the 24.4–24.5 eV range. The observed distributions were discussed in terms of the Saha equilibrium between He* and free electrons for high-energy states and the non-Saha equilibrium for low-energy states due to the collisional excitation to a neighboring state and low reionization rates. The total steady-state distributions of ns 1S, np 1P, nd 1D, ns 3S, np 3P, and nd 3D states were 0.048, 0.053, 0.18, 0.24, 0.13, and 0.35, respectively.
Effect of n=1 Buffer Layers on n=2 and n=3 Thin Films of Bi 2Sr 2Can-1CunOy
Authors: Takahiro Oku Takahiro Oku , Osamu Ajisaka Osamu Ajisaka , Hiroyuki Inuzuka Hiroyuki Inuzuka , Yuuji Horie Yuuji Horie , Teruaki Nomiyama Teruaki Nomiyama , Tomoyuki Miyazaki Tomoyuki Miyazaki 
Published: October 2002

The effect of n=1(2201) buffer layers on n=2(2212) and n=3(2223) thin films of Bi2Sr2Ca
n-1CunOy was investigated to reduce the strain caused by the lattice mismatch between the films and the substrates. The bilayer thin films of 2223/2201 and 2212/2201 were grown epitaxially on SrTiO3 (100) substrates by dc sputtering.
When the thickness of the buffer layer was 10–25 nm, the superconducting transition temperature increased by ∼20 K for 2223/2201 and by ∼6 K for 2212/2201.
The increase was attributed to the reduction of the strain from the experimental results of the full width at half-maximum of X-ray diffraction peaks, the length along the c-axis and the roughness of the film surface.
Femtosecond Optical Kerr Effect in the Gold Nanoparticle System
Authors: Hideyuki Inouye Hideyuki Inouye , Koichiro Tanaka Koichiro Tanaka , Ichiro Tanahashi Ichiro Tanahashi , Kazuyuki Hirao Kazuyuki Hirao 
Published: October 2002

We observed an ultrashort response of the gold nanoparticle system
that was as fast as 240 fs in a femtosecond optical-Kerr-shutter
experiment. The ultrafast response is attributed to the self-diffraction
of the pump pulse due to the transient grating. We estimated χ(3) of the gold nanoparticle system to be 2.0 ×10-8 esu in
the femtosecond region.
Size-Dependent Enhancement of Third-order Optical Nonlinearity in CuBr xCl1- x Nanocrystals Embedded in Glass
Authors: Li Yingli , Ohata Manabu , Satoshi Sasaki and Arao Nakamura Satoshi Sasaki and Arao Nakamura 
Published: October 2002

We have studied the size-dependence of the third-order optical nonlinearity in CuBrxCl1-x
(x=0.26±0.01) nanocrystals with radii ranging from 5.3-11.5 nm by means of degenerate four-wave mixing, time resolved luminescence and resonant luminescence experiments. The absolute value of third-order susceptibility χ(3) exhibits resonant behavior at the confined exciton level, and the resonant χ(3) increases with increasing crystallite radius R. Assuming a two-level atomic model, we have analyzed the size-dependence of χ(3) and obtained the R
2.1-dependence of the oscillator strength of confined excitons. The figure of merit increases from 0.65 to 3.4 esu·cm/s with increasing size.
Effects of Substrate Misorientation on the Formation and Characteristics of Self-Assembled InP/InGaP Quantum Dots
Authors: Guk Jeong Yong-Hwan Kwon 
Published: October 2002

The structural and optical characteristics of self-assembled InP/InGaP quantum dots grown by low-pressure metalorganic vapor phase epitaxy on GaAs substrates misoriented by 0°, 2°, 5°, 6°, and 35.3° toward (111)A are investigated. The analysis through atomic force microscopy and photoluminescence (PL) shows that the formation of quantum dots strongly depends on the orientation of the substrate. It is seen that large dots are more easily formed on an exactly (001) substrate but, with the increase of the degree of misorientation, the size of dots decreases and the density increases. In addition, the PL emission energy from InP dots is observed to be strongly blue-shifted with the increase in misorientation. From power-dependent PL measurement, the change of PL spectra is observed to be closely related to the size and density of the quantum dots.
Optical Recording in Ga and In-Doped Zinc Oxide Thin Films Grown by Radio-Frequency Magnetron Sputtering
Authors: Tatsuhiko Matsushita Tatsuhiko Matsushita , Akio Suzuki Akio Suzuki , Shogo Toda Shogo Toda , Takanori Aoki Takanori Aoki , Masahiro Okuda Masahiro Okuda 
Published: October 2002

Thin films of Zn-Ga-In oxide have been deposited on glass substrate at room temperature by rf magnetron sputtering with three targets of Zn, ZnO doped with 7 wt% Ga2O3 and ZnO doped with 7 wt% In2O3. In the oxide films prepared by this method, the difference in the transmittance, ΔT, between the annealed state(350°C × 30 min) and the as-deposited state was 41% at 380 nm, 61% at 390 nm and 72% at 400 nm. The ability to record on these oxide films without a protection layer, using SHG of Nd:YAG laser (λ=532 nm, 6 ns, 69 mW/µm2) was confirmed.
Single Crystal Growth of the Icosahedral Zn-Mg-Ho Quasicrystal
Authors: Taku J. Sato Taku J. Sato , Hiroyuki Takakura Hiroyuki Takakura , An Pang Tsai An Pang Tsai 
Published: October 2002

Single crystal growth of the icosahedral Zn-Mg-Ho quasicrystal has been performed using the Bridgeman method.
Composition of the starting alloy was selected as Zn46Mg51Ho3, so that the icosahedral phase directly precipitates from the liquidus phase.
A large single quasicrystal about 0.5 cm3 in size was obtained, and its composition was determined as Zn60Mg31Ho9.
The obtained quasicrystal shows an extremely high structural-perfection evidenced by the X-ray Laue reflection and neutron diffraction methods.
Uniform RF Discharge Plasmas Produced by a Square Hollow Cathode with Tapered Shape
Authors: Taichi Fukuda Taichi Fukuda , Akio Matsuoka Akio Matsuoka , Yoshiomi Kondoh Yoshiomi Kondoh , Minoru Sugawara Minoru Sugawara 
Published: October 2002

A square hollow cathode with a tapered shape (square HCT) is developed in order to produce highly uniform and dense plasmas (density ∼ 6×1010 cm-3) with a wide range of operating pressures. It is shown experimentally that the plasma density produced by the HCT is higher than that produced by a plane cathode from 0.02 Torr to 0.2 Torr. It is demonstrated experimentally that uniform plasmas can be produced by modifying the structure of the HCT for different operating pressures. It is shown that an additional outer hollow cathode is useful to compensate the nonuniformity of plasmas due to edge effects. With the use of the outer hollow cathode for the modified HCT, highly uniform plasmas are produced within almost the entire surface of the grounded square electrode.
Origin of the F-aggregate Centers in BaFX(X=Cl, Br) Single Crystals
Authors: Toshio Kurobori Toshio Kurobori , Shuichi Kozake Shuichi Kozake , Yukio Hirose Yukio Hirose , Karnati Somaiah Karnati Somaiah , Katsuyuki Inabe Katsuyuki Inabe , Masato Ohmi Masato Ohmi , Masamitsu Haruna Masamitsu Haruna 
Published: October 2002

Some new experimental evidence to determine the origin of the F-aggregate centers located in the near IR region in BaFX(X=Cl, Br) crystals is demonstrated. The attribution of the F-aggregate bands to a cluster of the F(X-) centers has been confirmed through a series of measurements on their emission in IR and the process of aggregates formation in BaFCl1-x
Br
x
mixed system. The F-aggregate bands at 860 and 1100 nm are assigned to the F(X-)2 and F(X-)4 centers, respectively, in view of the equilibrium between the F(X-) centers and the F-aggregate centers.
Imaging of Local Charge Density in an InAs/GaAs Two-Dimensional Heterostructure by Scanning Tunneling Microscopy
Authors: Hiroshi Yamaguchi Hiroshi Yamaguchi , Yoshiro Hirayama Yoshiro Hirayama 
Published: October 2002

We have studied the bias-voltage dependence of
constant-current images obtained by
scanning tunneling microscopy (STM) at 4.8 K
on an InAs thin film grown on GaAs (111)A substrates.
In-plane surface-height variation as large as 0.1–0.2 nm was detected
on the step-free region,
only with the negative sample voltages higher than -0.6 V.
Because the bias condition corresponds to the tunneling
of electrons accumulated in the InAs film to the STM tip,
we believe that the image reflects the local electron density
in InAs/GaAs two-dimensional heterostructures.
Selective Area Growth of GaN on Si Substrate Using SiO 2 Mask by Metalorganic Vapor Phase Epitaxy
Authors: Yasutoshi Kawaguchi Yasutoshi Kawaguchi , Yoshio Honda Yoshio Honda , Hidetada Matsushima Hidetada Matsushima , Masahito Yamaguchi Masahito Yamaguchi , Kazumasa Hiramatsu Kazumasa Hiramatsu , Nobuhiko Sawaki Nobuhiko Sawaki 
Published: October 2002

Selective area growth (SAG) of GaN on (111) Si substrate was studied using AlGaN as an intermediate layer. A hexagonal dot with a (0001) plane on the top and of a 5 µm or a submicron size was obtained using a patterned dot structure of silicon dioxide (SiO2) mask. The facet structure revealed that the <1120> axis of hexagonal GaN is parallel to the <110> axis of the Si substrate. The cathodoluminescence (CL) spectrum at 133 K exhibited a strong near-band-edge emission band for the submicron dots, which suggests excellent crystallinity. Epitaxial lateral overgrowth (ELO) of GaN on the Si substrate is demonstrated.
Electron Energy-Loss Spectroscopy Study of the Metal-Insulator Transition in (V1-xCrx)2O3 (x=0.012)
Authors: Hiroyuki Abe Hiroyuki Abe , Masami Terauchi Masami Terauchi , Michiyoshi Tanaka Michiyoshi Tanaka , Shik Shin Shik Shin 
Published: October 2002

Electron energy-loss spectra of (V1-x
Cr
x
)2O3 (x=0.012)
at the antiferromagnetic insulating (AFI), paramagnetic metallic (PM) and
paramagnetic insulating (PI) phases have been measured
using a high-resolution transmission
electron energy-loss spectroscopy (EELS) microscope.
The changes in the EELS spectra
at the transition from the PM phase to the AFI phase are interpreted
in a similar manner to the case of V2O3
[Jpn. J. Appl. Phys. 37 (1998) 584].
The change in the electronic structure
at the transition from the PM phase to the PI phase (Mott transition)
was revealed for the first time.
A sharp peak observed at 1.0 eV in the PM phase
did not appear in the PI phase.
The t
2g peak of
the O 1s → V 3d(t
2g) EELS spectra shows
an energy increase of 0.5 eV
at the transition from the PM phase to the PI phase.
This increase is interpreted to occur by
the splitting of the bonding e
g
π band,
which is partially filled in the PM phase,
into the fully occupied lower band and the unoccupied upper band,
and by the lifting of the unoccupied band to
an energy higher than the Fermi level in the PM phase.
The t
2g peak also shows a decrease in intensity
but an increase in the full width at half-maximum (FWHM) at the transition.
The decrease in intensity occurs due to
the decrease of the hybridization of the V 3d with the O 2p orbitals
resulting from an increase of the V–O distance.
The increase in the FWHM results from the lifting of the a
1g
* band
due to the decrease of the lattice constant c
H and
the splitting of the e
g
π and e
g
π* bands
each into two bands due to electron correlation.
A Novel Structure to Improve the Viewing Angle Characteristics of Twisted-Nematic Liquid Crystal Displays
Authors: Gong Shaoqin , Kanicki Jerzy , Xu Gang , Zhong JohnZ. Z. 
Published: October 2002

A numerical simulation of a novel wide viewing angle twisted-nematic liquid crystal
display (TN-LCD) structure has been performed. The simulated results indicate that this new
structure can provide an excellent gray level separation and a 50 : 1 contrast ratio that extends up
to around ±60° along both the vertical (V) and horizontal (H) directions. No reverse image is
expected over the ±65°H/±80°V range. No excessively dark or excessively bright images are
observed over the entire viewing angle range of the display. The fabrication process to achieve
this novel structure is also proposed.
Electron Affinity and Effect of Annealing on Heavily Boron-Doped Diamond Films
Authors: Wong Ka Wai , Lee Shuit Tong , Lin Zhangda , Lam Yat Wah , Kwok Raymund Wai Man 
Published: October 2002

A series of heavily boron-doped polycrystalline diamond films was studied. It was found that the electron affinity of the diamond surfaces increased with increasing doping concentration and the Fermi level was pinned at ∼0.35 eV above the valence band maximum (VBM). After annealing at ∼500°C, the electron affinity of all samples decreased and the Fermi level increased to 0.87 eV. These changes were concurrent with a decrease in the concentration of both boron and oxygen, and an increase in that of B
x
O
y
relative to elemental boron on the diamond surfaces. A model was proposed to explain the dependence of electron affinity on boron concentration, and to explain other changes observed upon annealing.
Temperature-Dependent Characteristics of the Inverted Delta-Doped V-Shaped InGaP/InxGa1-xAs/GaAs Pseudomorphic Transistors
Authors: Chang Wen-Lung , Pan Hsi-Jen , Wang Wei-Chou , Thei Kong-Beng , Cheng Shiou-Ying , Lour Wen-Shiung , Liu Wen-Chau 
Published: October 2002

The temperature-dependent characteristics of InGaP/In
x
Ga1-x
As/GaAs
pseudomorphic transistors with an inverted delta-doped V-shaped channel have
been studied. Due to the presented wide-gap InGaP Schottky layer and the
V-shaped channel structure, the degradation of device performance with
increasing the temperature is not so significant. Experimentally, for a
1×100 µm2 device, the gate-drain voltages at a gate leakage current of
260 µA/mm and the maximum transconductances g
m,max are 30 (22.2) V and
201 (169) mS/mm at the temperature of 300 K (450 K), respectively. Meanwhile, the broad
and flat drain current operation regimes for high g
m, f
T, and f
max
are
obtained.
Photoluminescence Dynamics of Aluminumquinoline/Oxadiazole Multilayer Structures
Authors: Tadahiro Nakazawa Tadahiro Nakazawa , Mitsuru Asano Mitsuru Asano , Shizuo Fujita Shizuo Fujita , Shigeo Fujita Shigeo Fujita 
Published: October 2002

Photoluminescence (PL) dynamics of aluminumquinoline/oxadiazole
(Alq3/PBD) multilayer structures,
which may possess a carrier confinement type-I energy lineup,
has been investigated by time-resolved PL spectroscopy
with a mode-locked Ti-sapphire laser. The decay time of the emission from PBD in the multilayer structure
was as fast as several picoseconds, in contrast to that from a PBD single layer, 1.7 ns,
and tended to increase with an increase in PBD thickness.
For the emission from Alq3, on the other hand,
only a slight increase in the decay time was observed
in the multilayer structure compared to a single layer.
These results indicate the rapid energy transfer from PBD to Alq3,
similar to that in semiconductor quantum well structures
with the type-I energy lineup.