bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Pressure on Electrical Conductivity of Doped Poly (p-Phenylene Sulfide)
Authors: Kawano Masaki , Shichijyo Shiro , Horiuchi Toshihisa , Matsushige Kazumi , Takemura Tetuo
Published: November 2005

The electrical conduction mechanism in poly(p-phenylene sulfide) (PPS) doped with iodine (I2) and tetracyanoethylene (TCNE) was investigated. X-ray diffraction and fluorescence X-ray experiments revealed that the doped TCNE and I2 exist mainly in an amorphous region and the desorption of doped I2 becomes very active with increasing temperature. The effect of pressure on the electrical conductivity was measured to determine the conduction mechanism in doped PPS, showing that electronic conduction takes place in TCNE-doped PPS, but ionic conduction in I2-doped PPS. In heat-treated I2-doped PPS, it was observed that electronic conduction also contributes to the conductivity at higher pressures. Furthermore, an additional increase in the conductivity was observed in TCNE and I2 double-doped PPS.
Improvements in MBE Grown AlxGa1-xAs/GaAs Single Quantum Well Structures Resulting from Dimeric Arsenic
Authors: Fischer R. , Sun Y. L. , Masselink W. T. , Klem J. , Klein M. V. , Morkoç H.
Published: November 2005

The effect of arsenic species on the photoluminescent response of GaAs/Al
x
Ga1-x
As single quantum well structures grown by molecular beam epitaxy was studied. At high substrate temperatures, e.g. 700°C, the luminescent properties were not highly sensitive to the arsenic species (dimeric or tetrameric) used. At lower substrate temperatures, however, the As species had a significant influence on the response. With a substrate temperature of 620°C, the intensity of the photoluminescence peak due to the quantum well increased by a factor of 2.5 in going from As4 to As2, primarily as a result of an improved inverted heterointerface. One proposed mechanism of improvement, the more effective cracking of arsenic at high substrate temperatures, is supported by these results.
The Effects of Tungsten-Halogen Lamp Annealing on a Selectively Doped GaAs/N-AlGaAs Heterostructure Grown by MBE
Authors: Tatsuta Shigeru , Inata Tsuguo , Okamura Shigeru , Hiyamizu Satoshi
Published: November 2005

The effects of tungsten-halogen lamp annealing on selectively doped (SD) GaAs/N-AlGaAs grown by MBE have been studied using Hall, C-V, and SIMS measurements. The changes in the electrical properties of SD GaAs/N-AlGaAs after lamp annealing have been greatly reduced in contrast to those of conventional furnace annealing. This was found to be caused primarily by the reduction of the diffusion of doped Si atoms in AlGaAs during the annealing. After lamp annealing at 900°C for 10 seconds, the electron mobility and the electron concentration of 2DEG of SD GaAs/N-AlGaAs heterostructure at 77 K remained very high, 74,000 cm2/Vs and 4.8×1011 cm-2, respectively. The values were 73% and 94% of the “as-grown” samples.
A New Two-Dimensional Electron Gas Field-Effect Transistor Fabricated on Undoped AlGaAs–GaAs Heterostructure
Authors: Katayama Yoshifumi , Morioka Makoto , Sawada Yasushi , Ueyanagi Kiichi , Mishima Tomoyoshi , Ono Yuichi , Usagawa Toshiyuki , Shiraki Yasuhiro
Published: November 2005

A new two-dimensional electron gas (2DEG) field-effect transistor (FET) which operates in an MOS transistor-like mode is fabricated on undoped AlGaAs–GaAs heterostructures grown by both molecular beam epitaxy and organometallic vapour phase epitaxy. This device with very simple structure is expected to have performance comparable to those of selectively doped heterostructure FETs and can easily be integrated.
Optical Emission Spectrum of Cl2 ECR Plasma in the GaAs Reactive Ion Beam Etching (RIBE) System
Authors: Asakawa Kiyoshi , Sugata Sumio
Published: November 2005

An optical emission spectrum was obtained from a Cl2 ECR plasma during GaAs etching in the RIBE system. Most emissive species were identified as atomic chlorines rather than molecular chlorines, typically when the ECR plasma was excited at the 300 W microwave power and the 500 V ion extraction voltage. From the relationship between the monitored emission intensity and the sputter yield as a function of the Cl2 gas pressure, the neutral etching species which chemically assist the ion beam etching undergone here were found to be the chlorine neutral radicals rather than the molecular species.
Ferroelectric Liquid Crystal with Extremely Large Spontaneous Polarization
Authors: Yoshino Katsumi , Ozaki Masanori , Sakurai Takao , Sakamoto Kazutami , Honma Masao
Published: November 2005

The greatest value ever reported for spontaneous polarization, as high as 4.2×10-8 C/cm2, is observed in DOBA-1-MBC. The relaxation frequency of this material determined from frequency dependence of the dielectric constant is higher than that of DOBAMBC by more than one order of magnitude. DOBA-1-MPC also indicates large spontaneous polarization as high as 1.8×10-8 C/cm2. These characteristics are discussed in terms of molecular structure of these ferroelectric liquid crystals.
New Electron Diffraction Techniques Using Electronic Hollow-Cone Illumination
Authors: Kondo Yukihito , Ito Takashi , Harada Yoshiyasu
Published: November 2005

Two electron diffraction techniques using electronic hollow-cone illumination have been developed to improve the convergent beam electron diffraction method. One of them gives clear whole patterns of the higher order Laue-zone lines without diffraction disks. This technique also allows taking any higher order Laue-zone patterns. The other gives twice as large a convergent angle as that of the conventional convergent beam electron diffraction method and allows the combined use of high resolution electron microscopy and convergent beam electron diffraction.
High Conductive P-Type Films of Si100-xAlx:H Fabricated by Co-Sputtering and Subsequent Annealing
Authors: Niu Hirohiko , Yoshizawa Izuru , Shikama Tomokazu , Matsuda Tetsuro , Takai Munezo
Published: November 2005

Films of Si100-x
Al
x
:H have been prepared by reactive co-sputtering and subsequently been annealed at 300∼600°C in flowing Ar. After annealing, the electrical conductivity of the film has increased by five orders of magnitude, where p-type conductivity of the order of 100 Ω-1cm-1 has been obtained when x=10∼19. X-ray diffraction has shown that the remarkable increase in the conductivity is closely related to partial crystallization of Si. Also measurements of infrared and optical absorption spectra for this system have been made.
High Frequency Time Modulation of the X-Ray Beam Diffracted from a LiNbO3 Crystal by Surface Acoustic Waves
Authors: Kikuta Seishi , Takahashi Toshio , Nakatani Shinichiro
Published: November 2005

The time modulation of the X-ray beam diffracted from a LiNbO3 crystal was observed when the surface acoustic wave (SAW) was excited on it by the piezoelectric effect. Since the SAW device vibrated with a frequency of 14.26 MHz, the X-ray intensity changed sinusoidally with a period of 70 nanoseconds. It is suggested that the present method can be used as a high speed X-ray chopper or shutter.
CO2 Laser Detection Using a Warm Carrier Device with a Thin Film Antenna
Authors: Harakawa Kenichi , Yasuoka Yoshizumi , Gamo Kenji , Namba Susumu
Published: November 2005

Thin film warm carrier devices have been fabricated by electron beam lithographic methods and demonstrated at 10.6 µm. The devices consisted of a narrow gold antenna, the top of which contacted p-type germanium through a 0.1 µm-diam. pinhole fabricated by focused ion-beam techniques. The device exhibited a distinguished antenna pattern for 10.6 µm wave length radiation.
Some Fundamental Properties of Ir Coated Impregnated Cathodes
Authors: Yamamoto Shigehiko , Taguchi Sadanori , Aida Toshiyuki , Kawase Susumu
Published: November 2005

Both electron emission and surface properties of the Ir coated impregnated cathode are studied by pulsed emission technique and surface analysis using Auger electron spectroscopy. Saturation current density is enhanced as much as 4 to 5 times that of the standard (uncoated cathode). The binding energy of the surface monolayer composed of Ba and O to the substrate, as well as that between Ba and O is strengthened by introducing Ir coating film, thus providing a more stable low work function surface than that of the standard cathode. It is found that under normal operation condition, the Ir film is easily alloyed with W substrate although it does not diffuse laterally over the surface.
Electrochromism of Er-Diphthalocyanine Complex Films in All Solid Display Cells
Authors: Yamamoto Hiroshi , Noguchi Masato , Tanaka Masaichi
Published: November 2005

Electrochromism of Er-diphthalocyanine complex (ErH(Pc)2) film was investigated with (Glass/ITO/ErH(Pc)2+LiF/LiF+CaCl2/Ag) solid cells. The fast change of color from green to purple-red was observed when positive voltages of about 2 V were applied to the ITO electrode, while negative voltages of about -2 V resulted in the change of color to blue-black. The former oxidation process was preceded by the migration of chlorine anions of CaCl2 in the dielectric layer. However, the mechanism of the latter reduction process remains vague.
A New Growth Method Using Source Current Control to Supply Solute Elements-Demonstration of In1-xGaxAs Case
Authors: Nakajima Kazuo , Yamazaki Susumu , Umebu Itsuo
Published: November 2005

A controllable method to supply solute elements into growth solutions during the growth was developed for the first time. DC electric current was passed through binary semiconductor compounds used as source materials of solute elements. The source compounds can be dissolved even into saturated solutions due to Peltier heating. In such a cource current-controlled (SCC) method, the composition of growing crystals can be controlled by an electric current passed through the source compounds. The SCC method is demonstrated for the liquid phase epitaxial growth of In1-x
Ga
x
As using InAs and GaAs as source compounds.
Approximation Formula of Cross-section for the Universal Potential Expression Proposed by Ziegler et al.
Authors: Kang Hee Jae , Kawatoh Eizoh , Shimizu Ryuichi
Published: November 2005

Recent progress in plasma physics has stimulated research on the universal potential applicable for low energy and light ion collisions. First, assessing typical potentials by comparing them with the experimental results of ICISS, we have found that the potential proposed by Ziegler et al. is the most appropriate. We have proposed an approximation formula of the cross-section of Ziegler's universal potential expression, which enables the total cross-section, nuclear stopping, etc. to be derived analytically.
Ion Beam Assisted Deposition of Metal Organic Films Using Focused Ion Beams
Authors: Gamo Kenji , Takakura Nobuyuki , Samoto Norihiko , Shimizu Ryuichi , Namba Susumu
Published: November 2005

50 keV Ar+ or focused Au+ were irradiated in a trimethyl aluminum atmosphere to investigate characteristics of ion beam assisted deposition. About 80 nm thick films were deposited at a dose of 1×1016/cm2. The film composition and its depth dependence was measured by Auger electron spectroscopy. It was found that the film contains oxygen, carbon and aluminum, and the atomic ratio varies across the film depth. The atomic ratio was 0.8(O):1.1 (C):1.4(Al) at the surface and was 0.8(O):3.3(C):1(Al) inside. A direct maskless pattern deposition was also done using 50 keV focused ion beams.
Pressure Dependence of Ferroelectric Transition and Anomaly in Bulk Modulus in Copolymer of Vinylidende Fluoride and Trifluoroethylene
Authors: Koizumi Naokazu , Murata Yukinobu , Oka Yoshio
Published: November 2005

Thermal expansion of copolymer of 52.8 mol-% vinylidene fluoride and 47.2 mol-% trifluoroethylene under varied hydrostratic pressure p up to 100 MPa was observed over a temperature range of 30 to 110°C. Pressure dependence of the ferroelectric transition T
t was evaluated as 0.318 K MPa-1 from the abrupt change in thermal expansion at the transition. This considerably large value of dT
t/dp was in good agreement with that found in the dielectric measurements. The bulk modulus vs temperature curve exhibited a conspicuous minimum at the transition of 337 K as is the case with ferroelectric crystals.
Electrical Properties of Oval Defects in GaAs Grown by MBE
Authors: Shinohara Masanori , Ito Tomonori , Wada Kazumi , Imamura Yoshihiro
Published: November 2005

Oval defect electrical properties and effects on FETs are investigated. The oval defect consists of a core and a hillock surrounding it. The core has a disturbed crystal structure, whereas the hillock has almost the same crystal quality as the normal epi-layers. Source-drain conductances decrease due to high defect resistivity. FET breakdown voltages are affected by the core location, that is, a leakage current increases due to dislocations and stacking faults which exist in the vicinity of the core-hillock boundary. These results indicate that oval defects should be eliminated in the achievement of electrical devices.
Raman Microprobe Study on Relaxation of Residual Stresses in Patterned Silicon-on-Sapphire
Authors: Yamazaki Ken-ichi , Uotani Ricardo Katsumi , Nambu Katsumi , Yamada Masayoshi , Yamamoto Keiichi , Abe Kenji
Published: November 2005

Residual stresses in crystalline silicon islands with concave and convex corners patterned on sapphire substrate are examined by Raman microprobe technique with a spatial resolution of ∼1 µm. It is found that the compressive stresses inherently remaining in SOS as-grown by conventional vapor phase epitaxy are relaxed at the edge and corners, depending on the degree of freedom in the relaxing directions.
Preparation of Nd-Doped SiO2Glasses by Axial Injection Plasma Torch CVD and Their Fluorescence Properties
Authors: Namikawa Hiroshi , Ishii Yoshiro , Kumata Ken , Arai Kazuo , Iida Ichio , Tsuchiya Toshio
Published: November 2005

To prepare Nd-doped SiO2glasses by axial injection plasma torch CVD, a special type of NdCl3gas generator for axial injection was developed and its optimum operating conditions were examined. The technical advantages and disadvantages of this method were discussed in comparison with previously reported tail injection plasma torch CVD. Although a large difference exists between these two methods, little difference in the fluorescence properties of the resultant glasses was observed.
Calibration of Vibration Transducers
Authors: Kuroda Kazuaki , Tsubono Kimio , Hirakawa Hiromasa
Published: November 2005

We discuss calibration of vibration transducers mounted on resonant mechanical antennas, introducing a calibrating method based on the reciprocal nature of electrostatic transducers.
Lorentz Electron Microscope Observation of Domain Walls in Fe–Nd–B Alloy Permanent Magnets
Authors: Suzuki Takao , Hiraga Kenji , Sagawa Masato
Published: November 2005

Domain and wall structures of sintered Fe77Nd15B8 permanent magnets have been examined by high voltage electron microscopy. A wall width of a 180° wall in a grain having the c-axis in the surface is about 50 Å, which agrees with that expected from a pure Bloch wall. However, a significant variation of a 180° wall image width along the c-axis was found, which is presumably due to a tilting of a wall plane with respect to the sample surface.
Picosecond Dynamics of Electron-Hole Plasma in GaAs/AlAs Multiple Quantum Well Structure
Authors: Tanaka Shosaku , Kuno Masaaki , Yamamoto Atsuya , Kobayashi Hiroshi , Mizuta Masashi , Kukimoto Hiroshi , Saito Hiroshi
Published: November 2005

Picosecond temporal character of high-density electron-hole plasma (EHP) in GaAs/AlAs multiple quantum well structure has been studied by means of time-resolved luminescence spectroscopy. The EHP with carrier density N
QW of 3–4×1017 cm-3 is formed, where carrier induced band-gap shrinkage of 10–20 meV takes place. Temporal character of luminescence due to the EHP is well explained by time variation of N
QW. Increase of N
QW results from carrier trapping with trapping time of ∼60 ps, and subsequent decrease of N
QW results from radiative recombination with bimolecular recombination coefficient of 4.5×10-8 cm3s-1.
Synthesis of Compositionally Graded A15 Nb–Si Films by Co-Sputtering
Authors: Nakamura Kiko , Asano Hidefumi , Maeda Yasushi
Published: November 2005

Using a compositional grading technique, metastable A15 Nb–Si films were synthesized by dual-target dc-magnetron sputtering. In the preparation of ground films, the Si-precoating of 40 to 80 Å thickness on the surface of sapphire substrates were found to have a great effect on suppressing the formation of a competing stable Ti3P-type phase. Compositional grading accompanying a 5 at%Si increase was carried out on the mostly single A15 Nb–21 at%Si ground films. The compositional grading resulted in a lattice parameter decrease and a T
c enhancement with a highest value of 13.9 K (1% onset).
Photoacoustic Spectroscopy on Powdered LiF Crystals for Thermoluminescent Dosimetry
Authors: Inabe Katsuyuki , Utsui Yoshinori , Kurobori Toshio , Takeuchi Nozomu
Published: November 2005

A spectrum similar to the optical absorption (OA) of X-irradiated LiF is observed by photoacoustic (PA) signal of microphone-detection method. A good agreement of the peak energy between the PA and the OA spectra is obtained for both F2and F2+bands. Similar thermal decay characteristic of the F2band in PA spectrum for powdered crystal to that in OA spectrum for single crystal indicates the usefulness of PAS for the study of TL process of powdered crystals.
The ∼100 meV Photoluminescence Peak in n-Type AlxGa1-xAs Grown by MOCVD
Authors: Sakamoto Masamichi , Okada Tsunekazu , Kawai Hiroji , Mori Yoshifumi , Kaneko Kunio
Published: November 2005

The low temperature photoluminescence peak at about 100 meV below the band-to-band transition in n-type Al
x
Ga1-x
As grown by MOCVD has been investigated. The peak was found to appear only at lower growth temperatures (Tg\lesssim740°C) and to appear for a series of samples grown immediately after an exchange of one section of the gas flow system. The presence of the peak was found to be closely related to the quality of the epitaxial layer.
Numerical Calculation of Ellipticities of Optical Eigen Modes in Cholesteric Liquid Crystals
Authors: Ouchi Yukio , Takezoe Hideo , Fukuda Atsuo , Kuze Eiichi , Goto Nobuyuki , Koga Masao
Published: November 2005

The ellipticities of cholesteric optical eigen modes are numerically calculated using a 4×4 matrix method. In the limit of (pitch/wavelength)=0, the polarization states generally tend to be linear for light propagating at a finite angle to the helical axis, but circular for light propagating along the helical axis. The singularity of the latter case is discussed on the basis of the calculated results for infinitesimal obliqueness. The polarization state is nearly linear in the whole frequency range except in reflection regions when light propagates in a medium of small dielectric anisotropy at a large angle to the helical axis.
High-Resolution Electron Microscopic Observation of Microcrystalline Domains in an Amorphous Fe84B16 Alloy
Authors: Hirotsu Yoshihiko , Akada Ryoji
Published: November 2005

A high contrast bright-field lattice imaging method in high resolution transmission electron microscopy and its application to the observation of microcrystalline domains in a partially decomposed amorphous Fe84B16 alloy are described. A selection of an optimum defocus value was found to be necessary in obtaining dimensional information of the microcrystalline domains by lattice imaging. It is concluded that bcc-like microcrystals of Fe with a size of about 1 nm were already formed in an as-quenched Fe84B16 alloy and they gradually grew up to a size of about 2 nm on a low temperature annealing.
Trench Coverage Characteristics of Polysilicon Deposited by Thermal Decomposition of Silane
Authors: Morie Takashi , Murota Junichi
Published: November 2005

Trench coverage of polysilicon deposited under low pressure using a SiH4–PH3–He system is investigated. The trench coverage becomes poorer with increasing SiH4 or PH3 partial pressure. This phenomenon is explained by assuming the contribution of Si2H6 formed by the polymerization of SiH4 in the gas phase to polysilicon deposition.
Effect of Magnetic Field on Residual Impurity Concentration in LEC GaAs Single Crystal
Authors: Terashima Kazutaka , Orito Fumio , Katsumata Tooru , Fukuda Tsuguo
Published: November 2005

Effect of magnetic field on impurity concentration incorporated into an LEC GaAs crystal has been studied. The contamination from crucibles and/or B2O3 has been found to tend to be reduced by application of a magnetic field during puling. The residual or intentionally doped carbon concentration decreased and doped chromium concentration increased under the magnetic field. These results are explained by assuming that the GaAs melt convection is suppressed and the effective viscosity of the melt is increased under the magnetic field.
A New Thermal-Oxidation Method for III-V Semiconductors
Authors: Takagi Yuhichi , Sugiura Osamu , Naruke Yasuo , Takahashi Toshio , Matsumura Masakiyo
Published: November 2005

A new thermal-oxidation method for III-V semiconductors that utilizes boiling water under high pressure conditions has been proposed and applied to InSb. The grown oxide has been characterized by RBS, AES and XPS measurements. The oxidation temperature was decreased below 200°C. The oxidized Sb distributed uniformly throughout the oxide and there was no pile-up of the Sb at the oxide-semiconductor interface. The resistivity of the oxide at 77 K was as high as 1014 Ωcm.
Composition Dependence of the Superconductivity in (Ba, Sr)(Pb, Bi)O3
Authors: Sakudo Tunetaro , Uwe Hiromoto , Fujiwara Takumi , Fujita Jun-ichi , Shiozawa Jun-ichi
Published: November 2005

The effect of Sr substitution for Ba on the superconducting transition temperature T
c of Ba Pb1-x
Bi
x
O3 ceramics has been investigated for series of various Pb/Bi ratio. At the semiconducting region (x=0.32), the shift of T
c is proportional to the added Sr-content. At the metallic region (x=0.20, there is a peak in the T
c vs Sr-composition diagram. The result is discussed in comparison with the pressure effect of the superconductivity of this compound reported previously.
Formation of Embedded Monocrystalline NiSi2 Grid Layers in Silicon by MBE
Authors: Ishizaka Akitoshi , Shiraki Yasuhiro
Published: November 2005

Overgrowth of monocrystalline silicon films has been achieved by the molecular beam epitaxy technique on patterned NiSi2 layers which were epitaxially grown on Si(111) substrates. The embedded NiSi2 grid layer can be used as the gate in a permeable base transistor and can form buried electrodes in other novel devices.
Distributed Feed Back Surface Emitting Laser Diode with Multilayered Heterostructure
Authors: Ogura Mutsuo , Hata Toshio , Yao Takafumi
Published: November 2005

The first distributed feedback surface emitting laser diode is realized with Al0.3Ga0.7As/GaAs multilayered heterostructure. Transverse junction-stripe (TJS) type lateral carrier injection is employed. The threshold current is 120 mA at 150 K with the active layer thickness of 6 µm. The temperature coefficient of the lasing wavelength is equal to a conventional DFB laser diode.
Reduced Damage Generation in GaAs Implanted with Focused Be Ions
Authors: Bamba Yasuo , Miyauchi Eizo , Arimoto Hiroshi , Takamori Akira , Hashimoto Hisao
Published: November 2005

Induced damage in focused-Be-ion-implanted GaAs was measured using Raman scattering spectroscopy. The amount of damage has been found to be reduced in the GaAs implanted with a Be ion beam focused to about 0.2 µm at 160 keV in comparison with the conventional unfocused case. Depth distribution profiles of the focused-ion-implant damage have shown that a considerable reduction of the damage occurs particularly at the near-surface region. This phenomenon is possibly caused by ionization annealing during high-dose-rate implantation.
Dispersion of the Linewidth Enhancement Factor in Semiconductor Injection Lasers
Authors: Ogasawara Nagaatsu , Ito Ryoichi , Tone Kiyoshi , Nakae Hiroshi
Published: November 2005

The dispersion of the linewidth enhancement factor α in an AlGaAs injection laser has been determined from the changes in spontaneous emission spectra as bias current is varied below threshold. It is demonstrated that the results are in good agreement with a simple model which takes account of the gain spectra and the associated anomalous dispersion of the refractive index in parabolic bands.
Origin of Surface Defects on Molecular Beam Epitaxially Grown GaAs
Authors: Ito Tomonori , Shinohara Masanori , Imamura Yoshihiro
Published: November 2005

A systematic study to eliminate the oval defect commonly observed in MBE grown GaAs layer is achieved, and the defect formation mechanisms are presented. A dramatic reduction (<103/cm2) of the oval defect is successfully made by reducing the growth rate to 0.4 µm/h at a growth temperature of 650°C. The Ga droplets produced in a Ga crucible are the most probable cause of the defect formed when the droplets adhere to a substrate surface. The dissociation of gallium oxides (Ga2O3, Ga2O) and thermally agitated gallium might be guilty of the droplet formation.
Evidence of the Existence of SiF4 Molecules in Fluorinated Amorphous Silicon
Authors: Kumeda Minoru , Yonezawa Yasuto , Shimizu Tatsuo
Published: November 2005

Evidence of the existence of a large number of SiF4 molecules is derived from the measurement of nuclear magnetic resonance of fluorine atoms at liquid He temperature for fluorinated amorphous silicon prepared by rf sputtering.
Small Surface Damage Facet Coating on InGaAsP/InP Laser by ECR Plasma Deposition
Authors: Wakita Koichi , Matsuo Seitaro
Published: November 2005

Electron cyclotron resonance (ECR) plasma deposition was applied to InGaAsP/InP buried heterostructure laser diode facet coating. The facet coated laser diodes had low leakage current diode characteristics and showed no degradation in lasing properties. Comparison with conventional deposition techniques such as plasma CVD and rf sputtering showed that ECR plasma deposition is quite suitable for the coating because very little crystal composition change and surface damage are induced during the coating process.
Influence of Power-Source Frequency on the Properties of GD a-Si:H
Authors: Matsuda Akihisa , Kaga Takao , Tanaka Hideo , Tanaka Kazunobu
Published: November 2005

The influence of power-source frequency on the film properties of glow-discharge (GD) amorphous silicon has been studied in the range from 10 kHz to 50 MHz. Mechanical property, rather than photoelectric properties of the film, is highly influenced by the frequency, i.e., compressive internal stress is stored in the film when deposited from SiH4 plasma operated by a frequency lower than 500 kHz. It has been demonstrated through mass spectrometric measurements that the internal stress is caused by ion bombardment on the growing surface of the film.
Improved 2DEG Mobility in Inverted GaAs/n-AlGaAs Heterostructures Grown by MBE
Authors: Sasa Shigehiko , Saito Junji , Nanbu Kazuo , Ishikawa Tomonori , Hiyamizu Satoshi
Published: November 2005

Electrical properties of an inverted heterojunction interface in selectively Si-doped GaAs/n-AlGaAs heterostructures were investigated. It was found that the origin of reduced 2DEG mobility in an inverted heterostructure is not interface roughness and/or background impurity pileup at the interface, but is diffused profile of doped Si impurities. Larger enhancement of 2DEG mobility at low temperature was obtained even in an inverted heterostructure by introducing a thick undoped AlGaAs spacer layer (Δ
t=100 Å) and lowering doping concentration of Si (N
d=5×1017cm-3); electron mobility as high as 7×104 cm2/Vs was observed at 5K with sheet electron concentration of 1×1012cm-2.
Observations of an Ordered Array of Defect Clusters in Lithium Fluoride Irradiated with 100 keV Electrons
Authors: Kawamata Yasuhiro , Hojo Saburo , Yada Keiji
Published: November 2005

In a transmission electron microscope, specimens of lithium fluoride are damaged by the electron beam. At room temperature, an ordered array of microscopic defect clusters of the same kind is formed in thin parts of the specimens. Diffraction patterns from the region where the ordered array of defect clusters is formed show satellite spots around the transmitted spot.
Efficient ITO/Se Heterojunction Solar Cells
Authors: Nakada Tokio , Kunioka Akio
Published: November 2005

Indium-tin-oxide (ITO)/selenium heterojunction solar cells with AM 1 conversion efficiencies as high as 3.3% have been fabricated by vacuum deposition. These cells have extremely high spectral response at short wavelengths, resulting in an efficiency of 6.5% under fluorescent light. The photovoltaic performance strongly depends upon the layer thickness of selenium (0.5∼10 µm) and of tellurium (0∼55Å) which is interposed to provide a sufficient mechanical bond between the oxide and selenium layers.
GaAs Growth Using an MBE System Connected with a 100 kV UHV Maskless Ion Implanter
Authors: Takamori Akira , Miyauchi Eizo , Arimoto Hiroshi , Bamba Yasuo , Hashimoto Hisao
Published: November 2005

A new molecular beam epitaxy (MBE) system coupled with a 100 kV maskless ion implanter via an ultrahigh vacuum (UHV) sample transfer module was constructed. This system can grow epitaxial layers with ion beam pattern-implantation without exposing a sample surface to the outer atmosphere. Buried Be implanted layers in MBE grown GaAs were fabricated using this apparatus. Because of the contamination-free UHV growth process, the photoluminescent intensity depth profile of the grown crystal showed no degradation at the interface where the MBE growth was interrupted for the ion implantation process.
Excitation and Propagation of ICRF Waves in INTOR Tokamak
Authors: Fukuyama Atsushi , Goto Akira , Itoh Sanae-Inoue , Itoh Kimitaka
Published: November 2005

Propagation equation of ICRF (ion cyclotron range of frequencies) waves is solved in a realistic geometry of INTOR tokamak, by employing a cold plasma dielectric. Impedance of the loop antenna in the low field side is calculated, and high loading resistance is obtained.
Time and Temperature Dependence of Density of Oxidation-Induced Stacking Faults in Diamond-Lapped Silicon
Authors: Ishihara Ichiro , Kaneko Hiroyuki , Matsumoto Satoru
Published: November 2005

The mechanically damaged silicon wafers are oxidized at temperatures in the range of 950–1150°C for 15 min-128 h in dry oxygen. Oxidation-induced stacking faults (OSF) are delineated by preferential etching. The density of OSF decreases with the increase of both oxidation time and temperature. Unfaulting reactions of OSF are detected by transmission electron microscopy. The annihilation of OSF seems attributable to unfaulting reactions due to the local concentration of the residual stress from mechanical damage and the impingement of OSF.
Disordering of Si-Doped AlAs/GaAs Superlattice by Annealing
Authors: Kawabe Mitsuo , Matsuura Nobuyuki , Shimizu Norisato , Hasegawa Fumio , Nannichi Yasuo
Published: November 2005

Effect of Si-doping levels and annealing temperature on disordering of 150-Å AlAs/150-Å GaAs superlattices is studied. The doping level of 4×1018 cm-3 cause disorder for 800°C, 2 h annealing, while the doping level of 1×1018 cm-3 does not induce disorder on this annealing condition. A superlattice which is doped with 1×1019 Si cm-3 disintegrates after 650°C, 2 h annealing and the diffusion coefficient of Al–Ga interdiffusion is estimated to be 3×10-17 cm2s-1. For 800°C, 2 h annealing the two undoped AlAs/GaAs layers adjacent to the doped region are disordered by Si diffusion.
High-Quality InGaAs Grown by Low-Pressure Metalorganic Vapor Phase Epitaxy Using a Vertical Reactor
Authors: Oishi Mamoru , Nojima Shunji , Kuroiwa Koichi
Published: November 2005

This paper presents the first successful application of a vertical reactor system to the MOVPE growth of high-quality InGaAs on InP substrates. The growth is carried out at low pressure, using triethylindium, triethylgallium, and arsine as source materials. Epitaxial layers with carrier concentrations 1015 cm-3, electron mobilities 8000 cm2/(Vs) (300 K) and 30000 cm2/(Vs) (77 K), and photoluminescence half-width 15 meV (77 K) are obtained. The composition variation over the grown layer surface is very small.
In Situ Heating Device for Real Time X-Ray Topography on Crystal Growth from the Melt
Authors: Kobayashi Tatsumasa , Imura Toru
Published: November 2005

To study the melting and solidification process of a metallic crystal, an in situ heating device for real time X-ray topography has been newly developed and used for the case of a pure aluminium single crystal. Solid-liquid interface remains macroscopically flat and facet growth is not seen. The perfection of slowly grown crystal is better than that of rather rapidly grown one.
Preparation of Electrochromic MoO3 Thin Films on ITO Glasses by Electrodeposition
Authors: Baba Nobuyoshi , Morisaki Shigeyoshi , Nishiyama Naoki
Published: November 2005

A new method of formation of electrochromic MoO3 thin oxide film on electric conducting glass (ITO glass) has been investigated for use in place of the conventional vacuum evaporation method. The ITO glass was cathodically electrolyzed in an aqueous solution of 0.007 mol/l lithium molybdate at a constant current density of ca. 3 A/m2 at 25°C. Blue, conductive and adhesive oxide film was obtained. Cycles of the coloration and bleach were repeated in the propylene carbonate solution of lithium perchlorate. A good reversibility was obtained.
Monolithic Integration of GaAs Photoconductive Detectors and MESFETs with Distributed Coupling to Optical Fibers
Authors: Matsuo Nozomu , Ohno Hideo , Hasegawa Hideki
Published: November 2005

In order to realize high speed, crosstalk-free interconnections with high noise immunity for very high speed IC's and systems, GaAs integrated photoconductive detector/FET receivers with a distributed coupling to optical fibers are developed. The distributed coupling enables a quick and simple connection between the integrated receiver and an optical fiber, with relatively low connection loss of -1.4 dB. The integrated receivers show response of 5 ns rise time for a 0.85 µm light pulse, which is limited by the surface effect of the detector.
Diffusion Profile of Some Metal Ions in Chalcogenide Amorphous Semiconductors
Authors: Okano Shuichi , Suzuki Masakuni , Fukada Noboru , Imura Takeshi , Hiraki Akio
Published: November 2005

Diffusion profile of Cu and Cd ions in amorphous As2Se1Te2 films has been studied by secondary ion mass spectroscopy (SIMS). Drive-in processes of the metal ions were carried out at 100°C which is below the glass transition temperature of a-As2Se1Te2. Cd was found to exhibit a familiar diffusion profile of Gaussian type while Cu was found to exhibit an anomalous diffusion profile. Extremely high diffusivity of interstitial Cu ions and electro-chemical reaction at the interface are considered to be responsible for anomalous diffusion profile.
High Performance (AlAs/n-GaAs Superlattice)/GaAs 2DEGFETs with Stabilized Threshold Voltage
Authors: Baba Toshio , Mizutani Takashi , Ogawa Masaki , Ohata Keiichi
Published: November 2005

Novel two dimensional electron gas FETs, which have a short period AlAs/n-GaAs superlattice for an electron supplying layer, were successfully fabricated for the first time using a molecular beam epitaxy and a conventional recessed gate process. The threshold voltage changes with changes in temperature (77–300 K) and resulting from light illumination are effectively suppressed (ΔV
T≈0.1 V). This stability is ascribed to low deep electron trap concentration in the superlattice. The high intrinsic transconductances of 325 mS/mm (77 K) and 146 mS/mm (300 K) are obtained for 3 µm gate FETs.
Screw Dislocations Decorated by Disclinations of C-Directors Observed in Thin Ferroelectric Smectic Liquid Crystal Cells
Authors: Ishikawa Ken , Uemura Tsuyoshi , Takezoe Hideo , Fukuda Atsuo
Published: November 2005

Characteristic defect lines, frequently observed in surface stabilized ferroelectric liquid crystal cells, are studied. They typically consist of thin lines perpendicular to the smectic layers and rather thick lines connecting them at their alternate ends. The neighboring parallel thin lines appear different from each other. The alternate appearance interchanges by reversal of the C-director field. The thin and thick lines are assigned to the screw and edge dislocations decorated with the singularity of C-directors. The difference in appearance of the thin lines is attributed to the relation of handedness between the screw dislocations and the s=+1 disclinations.
Nb3Sn–Pb Josephson Junctions Using Nb3Sn Formed by Reaction of Nb/Sn Dual-Layer Films
Authors: Tsuge Hisanao , Nordman James E.
Published: November 2005

Josephson tunnel junctions have been fabricated using Nb3Sn formed by the reaction at 800°C in a high vacuum between an rf sputtered Nb film and Sn film evaporated over the Nb film. An rf plasma oxidation technique was used for the formation of the tunneling barriers and Pb was deposited for the counter-electrodes. Current-voltage characteristics at 4.2 K show a sharp current rise at a voltage of 4.35 mV. The subgap resistance is more than 7 times the normal resistance. This work shows that high quality Nb3Sn base layers can be formed with a very simple and practical technique suitable for microdevice applications.
A Study of Silicon Transistor-Tip by Electron-Acoustic Microscopy
Authors: Takenoshita Hiroshi
Published: November 2005

Recent studies demonstrated the usefulness of electron-acoustic microscopy EAM to obtain internal information of specimens by an acoustic signal excited by an electron beam. Using an Si Tr-tip as a specimen, various modes of SEM and electron acoustic image EAI of EAM were observed in situ at the same areas. Observation of EBIC images and EAI under varying bias applied to the specimen indicated that the relationship in the contrast changes between EBIC images and EAI. This suggests that the EBIC signal plays a part in generation of the acoustic signal.
Influence of Phosphorus Evaporation from Melt on InGaP/GaAs LPE Growth
Authors: Kato Takamasa , Matsumoto Takashi , Yoshioka Yasuhiro , Kobayashi Masaya , Ishida Tetsuro
Published: November 2005

The evaporation of phosphorus from the melt during LPE growth process causes poor reproducibility of melt composition and crystal growth. In this letter, we show the effect of applying additional phosphorus vapor pressure onto the melt surface on the epitaxial layer morphology and photoluminescence spectrum. It is clear that applying 1-Torr phosphorus vapor pressure on the melt surface is very effective in maintaining a constant melt composition during the growth process. LPE layers with good crystalline qualities have been grown reproducibly on both (111)B and (100) GaAs substrates.
Fabrication of Low OH and Low Loss Fluoride Optical Fiber
Authors: Mitachi Seiko , Ohishi Yasutake , Takahashi Shiro
Published: November 2005

Low OH and low loss fluoride optical fiber of 6.3 dB/km at 2.13 µm is obtained by dry processing technique. This is the lowest loss fluoride fiber yet reported. The OH peak at 3 µm is reduced to less than one-hundredth that of conventional fiber preparation.
MBE Growth of High-Quality InP Using Triethylindium as an Indium Source
Authors: Kawaguchi Yoshihiro , Asahi Hajime , Nagai Haruo
Published: November 2005

High-quality InP is grown on (100) InP substrates by molecular beam epitaxy using triethylindium and red phosphorus. Introduction of hydrogen during growth is found to be effective in improving crystal quality. Epitaxial layers are n-type and the highest achieved 77 K mobility is 32000 cm2v-1s-1 with a carrier concentration of 8.7×1014 cm-3.
Interrelation of Si Internal Stress and Si/SiO2 Interface Stress
Authors: Iechi Hiroyuki , Satoh Shiro
Published: November 2005

Both Si/SiO2 interface stress (σint) and Si internal stress (σsi) of identical CZ-Si wafers with oxidized SiO2 film are estimated and analyzed. In the oxidation temperature from 1000 to 1100°C, temperature dependence of σint and σsi is similar in the small warpage region, but quite different in the large warpage region. Furthermore, it is observed that the values of σint are one order of magnitude larger than those of σsi. These experiments suggest that the relaxation phenomenon occurs near Si/SiO2 interface, and the relaxation mechanism in the small warpage region differs from that in the large warpage region.
Preparation and Magnetic Properties of Sm-Co Films with High Substrate Temperatures
Authors: Munakata Makoto , Goto Kimiyoshi , Shimada Yutaka
Published: November 2005

Thin magnetic films with an approximate composition of Sm2Co7.8 were prepared on quartz substrates at high temperatures from 150° to 750°C by rf sputtering method. Film structures and magnetic properties have been studied. With the increase of the substrate temperature, the coercive force increases and then decreases through a well-reproducible maximum value of 11 kOe at 400°±50°C. It is shown by X-ray analyses that fine crystallites of SmCo5, Sm2Co7 and Sm2Co17 phases coexist in films with high coercive forces.
Effects of |H2Se|/|DMZn| Molar Ratio on Epitaxial ZnSe Films Grown by Low-Pressure MOCVD
Authors: Yoshikawa Akihiko , Tanaka Keiji , Yamaga Shigeki , Kasai Haruo
Published: November 2005

Effects of the |H2Se|/|DMZn| molar ratio on the electrical and optical properties of nominally undoped ZnSe films grown on (100) GaAs substrates by low-pressure MOCVD have been studied. It was found that the carrier concentration in the films decreases with the molar ratio, while the luminescence intensity ratio between the NBE emission and that from deep centers increases. Furthermore, the distance between an inlet nozzle for DMZn and the substrate was found to give qualitatively the same effects to the properties of ZnSe films as those by the molar ratio.
Active Distributed Reflector Lasers Phase Adjusted by Groove Region
Authors: Koentjoro Sekartedjo , Broberg Björn , Koyama Fumio , Furuya Kazuhito , Suematsu Yasuharu
Published: November 2005

Active distributed reflector lasers, where the phase adjustment is accomplished by a groove in the middle part of the cavity, are proposed. Design considerations for the groove are given. Phase adjusted lasers emitting at 1.5 µm were fabricated using mass transport technique. CW operation at room temperature was achieved and single longitudinal mode spectra were observed. Below-threshold spectra show that the mode degeneracy of conventional DFB lasers is avoided, which indicates that lasing occurs almost at the Bragg wavelength.
Excitonic Absorption Spectra of GaAs–AlAs Superlattice at High Temperature
Authors: Iwamura Hidetoshi , Kobayashi Hideki , Okamoto Hiroshi
Published: November 2005

Optical absorption spectra of MBE grown GaAs–AlAs superlattices with various thickness of the potential-well layer were measured in the temperature range up to 500 K. The excitonic absorption peak is observed even at a temperature of 500 K or higher. The broadening parameter \varGamma for the exciton peak was determined by a curve fitting. This parameter determines the temperature limit below which double absorption peaks due to heavy and light hole exciton are observed.
Wide-Band Frequency Response Measurements of IR and FIR Detectors by Diode-CO2 Laser Heterodyne Detection
Authors: Koizumi Toshiro , Tashiro Hideo , Nagasaka Keigo , Namba Susumu
Published: November 2005

By mixing tunable diode laser radiation and CO2 laser radiation, wide-band heterodyne signals were generated for precise frequency-response measurements of fast infrared detectors. Measuring capability of frequency range over 1 GHz was demonstrated using HgCdTe and Ge(Ga) detectors. The system operated at 10 µm proved efficiently applicable even to far-infrared detectors.
ESR and Raman Studies on Hydrogenated Amorphous Si–Sn
Authors: Morimoto Akiharu , Kataoka Toyotaka , Shimizu Tatsuo
Published: November 2005

Results of electron spin resonance (ESR) and Raman scattering measurements are reported for hydrogenated amorphous Si–Sn (a-Si1-x
Sn
x
:H) films prepared by r.f. sputtering of planar-magnetron type at a substrate temperature of 100°C. Sn dangling bonds are observed by ESR measurement in a–Si1-x
Sn
x
:H films. This is the first observation of Sn dangling bonds by ESR. In Raman spectra, Si–Si, Si–Sn and Sn–Sn vibrational bands are observed at 480, 310 and 150 cm-1, respectively.
New Scheme of Cannonball Target Driven by Ion Beam
Authors: Imasaki Kazuo , Miyamoto Shuji , Higaki Satoshi , Ozaki Tetsu , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

A new concept of ion beam target is proposed. Ion beam energy was injected inside a solid gold shell. Energy of the radiation converted from the beam was confined and transported inside. This effect was called the Mahobin effect. If the Mahobin target is compared with a direct driven target, several advantages such as power amplification, brightness reduction and higher gain can be expected. Total implosion effciency was estimated to be more than 10%.
Spin Polarization of Electron-Excited Secondary Electrons from a Permalloy Polycrystal
Authors: Koike Kazuyuki , Hayakawa Kazunobu
Published: November 2005

Spin polarization of electron-excited secondary electrons from a permalloy polycrystal has been measured as a function of incident beam energy, E
i, from 200 eV–2 keV. A spin polarization of 6% at E
i=200 eV increases with E
i and reaches a saturation value of 11% at E
i=1.1 keV. This polarization value remains constant up to E
i=2 keV. An intrinsic decrease in surface magnetization is proposed as a possible cause of this feature.
Lateral Photovoltaic Measurements of Electrical Properties of SiAl:H/n-Type Si Structures
Authors: Shikama Tomokazu , Okada Yoshihiro , Hamana Takashi , Niu Hirohiko , Matsuda Tetsuro , Takai Munezo
Published: November 2005

For the measurement of p-n junction characteristics, exemplified by those of the junction formed by an amorphous-microcrystalline SiAl:H film on a crystal Si, a modified lateral photovoltaic method has been developed in which electrodes covering the p and n layers are needless.
Using this method, I
0 and m in the I-V equation of the junction, I=I
0[exp
{q
V/(m
k
T)}-1], have been determined with a high degree of accuracy. To succeed in this measurement, the leakage conductance g
L at the periphery of the junction must be negligible. If g
L is not negligible, its existence can be confirmed by this LPV method.
An in situ Raman Study after n-Doping of a cis-Rich Polyacetylene Electrode in an Electrochemical Cell
Authors: Lefrant S. , Bernier P. , Kaner R. B.
Published: November 2005

We present the first direct observation of the Raman and ESR spectra of a polyacetylene film used as an electrode in a rechargeable battery. We follow the evolution of these spectra during the Li doping of the film and compare the observed behaviour with the case of chemical Li doping of the same material.
A+ Center and A+ Related Complex in Zinc Doped Germanium
Authors: Nakata Hiroyasu , Ichikawa Yohei , Otsuka Eizo
Published: November 2005

Far-infrared photoconductivity measurement at 1.5 to 10 K confirms the existence of an A+ center and an A+ related complex in zinc doped germanium. Hole binding energies of the A+ center and the A+ related complex are estimated as about 2 and 7 meV, respectively, from the lower energy threshold of photoconductivity and the dependence of photoconductivity on temperature.
Characteristics of WN/GaAs Schottky Contacts Formed by Reactive RF Sputtering
Authors: Yamagishi Haruo
Published: November 2005

WN film formation by a reactive rf sputtering and WN/GaAs Schottky contact characteristics were investigated with the intent of forming a gate for self-aligned MESFETs. WN/GaAs contacts show good Schottky diode characteristics even after high temperature annealing. Both the ideality factor n and flat band barrier height φB0
C of contacts showed nearly constant values of about 1.1 and 1.15 eV, respectively, for annealing at about 800°C and for annealing longer than 20 min.