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Ceramic particles, such as titanium oxide and indium tin oxide, are expected to be used as electric or catalytic materials for various applications. In this work, we progressed to employ the irradiation with an electron beam as the nonequilibrium reaction field for ceramic composition, and we successfully obtained the basic technology for a ceramic thin-film fabrication using a field emission (FE) electron beam with low energy resolution having a half width under 100 meV that had a homogeneous planar electron emission as the nonequilibrium reaction field. In particular, ZnO particles synthesized by electron beam irradiation show selective crystal bridging along the c-axis during FE electron beam irradiation, which is important for synthesizing poly-ZnO crystals without a heating process, because the energy fluctuations of FE electron beams are small and affect the directionality of ZnO crystal growth along the c-axis. This accomplishment may make a significant contribution to the analysis of the formation mechanism of ZnO particles with a uniform morphology and crystal structure by the FE electron beam during the crystallization. Moreover, we will be able to provide basic elements for next-generation nanodevices with highly functional properties by controlling each terminal crystal interface of metals, ceramics, and semiconductors with this technique.

α-Ga2O3 is a metastable phase of gallium oxide (Ga2O3) and is important for application in solar-blind region optoelectronic devices. High-quality α-Ga2O3 thin films can be grown by mist chemical vapor deposition (mist-CVD). We systematically investigate the growth mechanism of α-Ga2O3 by mist-CVD using acetylacetonated Ga source solutions. We propose a growth mechanism of α-Ga2O3 in mist-CVD in which acetylacetonate ligands anchor to surface hydroxyls and Ga–O bonds are formed by a ligand exchange mechanism. The origin of oxygen atoms and impurity concentration profiles in grown α-Ga2O3 thin films are examined by secondary ion mass spectroscopy.

This article reviews our recent work on photostimulated ion desorption (PSID) from molecules condensed at low temperature. We have used electron–ion coincidence (EICO) spectroscopy combined with synchrotron radiation. The history and present status of the EICO apparatus is described, as well as our recent investigations of condensed H2O, NH3, CH3CN, and CF3CH3. Auger electron photon coincidence (AEPICO) spectra of condensed H2O at the O:1s ionization showed that H+ desorption was stimulated by O:KVV Auger processes leading to two-hole states (normal-Auger stimulated ion desorption (ASID) mechanism). The driving forces for H+ desorption were attributed to the electron missing in the O–H bonding orbitals and the effective hole–hole Coulomb repulsion. The normal ASID mechanism was also demonstrated for condensed NH3. The H+ desorption at the 4a1←O(N):1s resonance of both condensed H2O and condensed NH3 was found to be greatly enhanced. Based on the AEPICO spectra the following four-step mechanism was propose...

This work is an investigation of the desorption by O 1s excitation of ions from Si(100) reacted with water. Photoelectron, photostimulated desorption, and electron-ion coincidence spectroscopy are used to observe the process. When the incident photons have energy levels which are near the 1s threshold of O, they induce Auger decay that is accompanied by shakeup/off excitation and cascade Auger decay, and they are shown to be the main factor responsible for desorption in this case. When the photons have energy levels which are above the shakeup threshold, most of the desorption that occurs is a result of the shakeup excitation that accompanies the core excitation. In both cases, the desorption is induced by the respective multihole final states. The ion desorption yield for the two-hole final states of the normal process of Auger decay is small. The results are discussed, with the help of the Auger electron spectra, mainly in terms of the lifetime of the final state of Auger decay.

We used the energy-selected-photoelectron photoion coincidence (ESPEPICO) method to study site-specific fragmentation caused by C:1s photoionization of 1,1,1-trifluoro-2-propanol-d1 [CF3CD(OH)CH3, TFIP-d1] on a Si(100) surface. High-resolution electron energy loss spectroscopy showed that TFIP-d1 is dissociatively chemisorbed like (CF3)(CH3)CDO–Si(100), and different chemical shifts at the three carbon sites were observed by photoelectron spectroscopy. The site-specific fragmentation evident in the ESPEPICO spectra of the sub-monolayer at room temperature indicates that the TFIP-d1 there has an O–Si bond oriented in the trans position with respect to the C–CF3 bond. Here we discuss the fragmentation processes in light of the results obtained with the ESPEPICO method and the Auger-electron photoion coincidence method.

We have developed a new electron–ion coincidence apparatus combined with synchrotron radiation in order to examine the various ion desorption mechanisms related to the Auger process induced by core excitation. Photon stimulated ion desorption (PSID) of a poly-methylmethacrylate (PMMA) thin film has been investigated by this apparatus. The PSID of PMMA induced by carbon core excitation has been examined using Auger electron yield, total ion yield, resonant Auger electron, and Auger electron–photoion coincidence (AEPICO) spectra. The spectrum of the total ion yield divided by the Auger electron yield shows that the desorption efficiency is largely increased at the resonant excitation of carbon 1s electron in the O–CH3 side chain to σ*(O–CH3) orbital. In AEPICO measurement, H+ and CHn+ (n=1–3) ions are observed at various resonant excitations. The AEPICO signal intensity depends on the Auger electron energy. Particularly, the CH3+ ion desorption in coincidence with Auger electron at 270 eV shows strong enhan...

The vibrational modes of the β-Si3N4 Raman active bands appearing in the wave number region between 110 and 1100 cm−1 were determined by the polarization and the crystallographic orientation dependence of the Raman intensities of the bands using micro-Raman spectroscopy. The laser beam was focused onto a single grain with the shape of a regular hexagon or elongated hexagon on the sintered ceramic plate. The three intense bands appearing at about 185, 208, and 230 cm−1 were attributed to the vibrational modes of E2g, Ag, and E1g, respectively. The remaining peaks were also assigned to the irreducible representations.

We used photoelectron spectroscopy and the energy-selected-photoelectron photoion coincidence method to study site-specific fragmentation following Si:2p photoionization of 1-trifluorosilyl-2-trimethylsilylethane [F3SiCH2CH2Si(CH3)3, FSMSE] condensed on a Au surface. The photoelectron spectrum of FSMSE has two peaks for 2p-electron emission: One for the Si atom bonded to three methyl groups (Si [Me]) and one for the Si atom bonded to three F atoms (Si [F]). H+ and F+ ions are predominantly desorbed coincidentally with the Si[Me]:2p and Si[F]:2p electrons.

Energy-selected electron-ion coincidence spectroscopy for the study of surface dynamics combined with synchrotron radiation (SR) was developed. The equipment consists of an electron gun, a cylindrical mirror analyzer (CMA), and a time-of-flight (TOF) ion mass spectrometer. A sample surface was excited by SR, and energy of the emitted electron was analyzed by the CMA. The TOF spectrum of the desorbed ions was measured taking the energy-analyzed electron signal as the starting trigger. The ions coincidently desorbed with the electron gave a characteristic peak in the TOF spectrum. The apparatus was evaluated on the basis of photoelectron–photoion coincidence (PEPICO) and Auger electron–photoion coincidence (AEPICO) measurements of H2O condensed on gold foil. The results demonstrate that PEPICO and AEPICO combined with SR are powerful methods for investigating the ion desorption induced by core-level excitations.

Atomic force microscopy with a conductive probe has been used to study both the topography and the electronic properties of 10-nm-scale self-assembled InAs quantum dots (QDs) grown by molecular beam epitaxy on n-type GaAs. The current flowing through the conductive probe normal to the sample surface is measured for imaging local conductance, while the deflection of cantilever is optically detected for disclosing geometrical structure. The conductance on InAs QDs is found to be much larger than that on the wetting layer, allowing imaging of QDs through measurements of local current. We attribute this change in conductance to the local modification of surface band bending associated with surface states on InAs QD surface. Mechanisms of electron transport through QDs are discussed based on current–voltage characteristics measured on QDs of various sizes.

We have constructed a new scanning tunneling microscope (STM) using two mechanical stages. One (z stage) is for approaching the tip to the sample surface and the other (x stage) is for one‐dimensional movement of the sample to observe a specific area of the sample surface. The stages move so precisely that the distance between the tip and the sample is constant during the sample movement. It enables us to find the specific area quickly. Another feature of the STM is a novel data accessing method which realizes high‐speed scanning tunneling spectroscopy (STS) measurement. A great deal of data are accessed at high speed by a personal computer equipped with 32‐megabyte random access memory (RAM). Using this system, STM and STS measurements of cleaved (110) surfaces of Ga0.47In0.53 As/InP multiquantum wells were performed in air.

The evolution of GaAs ridge structure formation by molecular beam epitaxy on a patterned substrate has been investigated using an ultrahigh vacuum atomic force microscope. It is found that the morphology of ridges can be quite irregular with random formation of various facets in the intermediate phase of growth, but self-smoothing processes of the lateral facets take place later on, leading to very sharp and smooth ridge structures in the end. The ridge top is quite sharp and straight with the height fluctuation of within 1–2 nm over the length of 1.4 μm. The role of the Ga atom flows from the side (111)B surfaces to the top (001) surface and their local modulations are considered to account for these observations.

A new spherical grating monochromator with translational and rotational assembly including a normal incidence mount (SGM‐TRAIN) is under construction at BL 5A of the UVSOR Facility, IMS, and its design concept is reported. The following points have been taken into account in the design: (1) Energy range of 5–250 eV, (2) use both of undulator and bending magnet radiation, (3) linear and circular polarizations, (4) spectral purity, (5) resolution, and (6) length of beamline. It should be stressed that the SGM‐TRAIN is useful for experiments where circularly polarized synchrotron radiation is used. Moreover, the SGM‐TRAIN has the advantage that the small emittance of storage ring and the large space for a long beamline are not necessary.

An InP surface thermally cleaned in an arsenic flux was observed using an ultrahigh‐vacuum scanning tunneling microscope (UHV‐STM). In the STM image, about 1.6 nm period lines of 0.8 nm width with two rows were observed along the [110] direction. This result suggests that the surface comprises two In‐In dimers and two missing dimers per (4×2) cells.

KrF- and ArF-excimer-laser-induced absorption of silica glasses produced by electric melting and flame fusion of synthetic silica powder were investigated. The growth of KrF-laser-induced absorption was more gradual than that of ArF-laser-induced absorption. Induced absorption spectra exhibited a peak at about 5.8 eV, of which the position and width differed slightly among samples and laser species. Widths of ArF-laser-induced absorption spectra were wider than those of KrF-laser-induced spectra. KrF-laser-induced absorption is reproducible by two Gaussian absorption bands peaking at 5.80 eV with full width at half maximum (FWHM) of 0.62 eV and at 6.50 eV with FWHM of 0.74 eV. For reproduction of ArF-laser-induced absorption, Gaussian bands at 5.41 eV with FWHM of 0.62 eV was necessary in addition to components used for reproducing KrF-laser-induced absorption. Based on the discussion of the change of defect structures evaluated from change of absorption components, we proposed that the precursor of the 5.8-eV band ascribed to E′ center (≡Si·) is ≡Si−H HO−Si≡ structures formed by the reaction between strained Si−O−Si bonds and interstitial H2 molecules during the irradiation.

We fabricated pentacene field-effect transistors using polysilsesquioxane (PSQ) as a gate dielectric material that can be cured at sufficiently low temperatures for low cost plastic substrates. The surface roughness of the PSQ films were reduced by the introduction of 3-methacryloxypropyl groups, and their surface energy was controlled to match with that of the pentacene layers by the introduction of phenyl groups. Consequently, the carrier mobility was improved by two orders of magnitude and reached 0.38 cm2 V−1 s−1.

A new method to produce electrically steady ZnO films without any heating process has been developed by using plasma and electron beams to facilitate bonding between the metallic component and the oxygen on coated ZnO films. Both plasma atmosphere and electron beams can function as sources of nonequilibrium bonding energy, forming bridges between the zinc present in the zinc complex and the oxygen in the ZnO particles to construct a zinc-oxide thin film. Our results confirm that it is possible to achieve low conductive characteristics by controlling the acceleration voltage of electrons used to irradiate the ZnO coating. The electrically steady films fabricated have various potential applications, being particularly well-suited to electrical devices on a plastic medium.

We have investigated contact and channel resistances of organic field-effect transistors (FETs) based on benzodithiophene (BDT)-dimer films deposited on thin pentacene layers used as crystallinity control layers (CCLs). The contact resistance of source/drain electrodes made of conductive organic films instead of Au films has been reduced for pentacene-CCL/BDT-dimer FETs; the carrier mobility has been improved to 1.2 cm2 V−1 s−1 at maximum. Because the channel resistance of the pentacene-CCL/BDT-dimer FETs is found to be lower than that of reference pentacene FETs, the carrier transport in the BDT-dimer layers is more important than that in the pentacene CCLs for the high mobility.

The carrier transport in the benzodithiophene (BDT)-dimer films plays significant role for high carrier mobility of BDT-dimer field-effect transistors (FETs) using very thin pentacene layers as crystallinity control layers (CCLs). When the grains of the BDT-dimer films are small, the carrier mobility is not only low but also depends on the average thickness of the pentacene-CCLs. However, it is independent from the thickness of the CCLs when the grain size of the BDT-dimer films is large enough, and becomes as high as 0.76 cm2 V−1 s−1. This result shows that the high carrier mobility of pentacene-CCL/BDT-dimer FETs is due to the carrier transport in the BDT-dimer films.

We have significantly improved the crystallinity of vacuum-evaporated benzodithiophene (BDT)-dimer films using pentacene crystallinity control layers. The pentacene molecules evaporated on hexamethyldisilazane-treated SiO2 surfaces first form many small islands. Then, the islands grow two dimensionally. We used thin pentacene films with surface coverage of approximately 90% as crystallinity control layers, and deposited 30-nm-thick BDT-dimer films on them. Micron-scale planar grains are observed in atomic force microscopy images of the BDT-dimer films. The highly anisotropic shape of the grains indicates that the BDT-dimer films of good crystallinity have been obtained. The field-effect transistors based on the BDT-dimer films showed excellent hole mobility of 1.2cm2V−1s−1 at maximum.

An electron gun constructed using carbon-nanofiber (CNF) emitters and an electrostatic Einzel lens system has been characterized for the development of a high-resolution x-ray source. The CNFs used were grown on tungsten and palladium tips by plasma-enhanced chemical-vapor deposition. Electron beams with the energies of 10E20 keV were focused by the electrostatic lens and impinged on a W target for x-ray radiography. Analyzing the recorded x-ray radiographs, the focal spot size of the electron beam extracted from the CNFs was estimated to be D50 microm in diameter. Superior performance was realized by using CNFs with larger fiber radii (100-500 nm) grown sparsely on the metal tips, which were installed in a holder at the short length L=0.5 mm.

The adsorption of formic acid (HCOOH) on the Si(100)c(4×2), Si(100)(2×1), Si(100)9° vicinal and Si(111)(7×7) surfaces has been studied by means of high resolution electron energy loss spectroscopy. Formic acid is partially dissociated to form the unidentate formate species (HCOO) and H adatoms on these surfaces at both 90 and 300 K. The formate species is bonded to the Si surface with a covalent bond formed between one of its oxygen atoms and the dangling bond of the surface Si atom. A condensed multilayer of molecular formic acid is formed after the Si surface is saturated with the formate species at 90–150 K. The thermal decomposition mechanism has been studied in detail. The decomposition temperatures of the formate species on Si(100) and Si(111) are ∼600 and 550 K, respectively. It appears that the surface steps do not play an important role in the Si–HCOOH interaction. As the formate‐covered surface is exposed to atomic hydrogen, methylendiolate (H2COO) is formed on the Si surface.

High‐pressure experiments using a multiple anvil high‐pressure system with sintered diamond anvils are presented and discussed. Pressures in excess of 41 GPa were obtained, on the basis of the lattice constants of gold determined by the in situ x‐ray diffraction technique using synchrotron radiation.

High‐resolution electron energy loss spectroscopy (EELS) has been applied to the study of the Si(111)(7×7)–H2O(D2O) system. At 300 K, H2O(D2O) is partially dissociated on the Si(111) surface to form the SiOH(SiOD) and SiH(SiD) species. Angle and primary‐electron‐energy dependences of the vibrational loss intensities were measured. Relative contributions to the vibrational excitations of the dipole, impact, and resonance mechanisms were estimated. The O–H(O–D) stretching and Si–O–H (Si–O–D) bending vibrations are partly excited by the resonance mechanism in the primary energy region of Ep ≂2–7 eV. EELS spectra of the Si(111) surface exposed to H2O(D2O) at 300 K and of the same surface heated to ∼700–900 K are presented, and surface reaction mechanisms are discussed.

Surfaces of microcrystalline silicon films prepared by the glow discharge method have been investigated by a scanning tunneling microscope (STM) in air. Grain‐like structures of 30–80 nm size which correspond to transmission electron microscope data have been observed. The film surface was found to be geometrically rather flat but the structure was observed electrically, that is, the resistivity seemed to be inhomogeneous due to preferential oxidation. Also, degradation of STM images of a HF‐etched microcrystalline silicon surface has been observed for the first time.