The present reconstruction method of Atom Probe Tomography (APT) has the problem that the parameter, in particular the shank angle which represents the region the signal of APT is detectable, is adjusted according to the internal length reference of the sample. The reliable APT reconstruction image could not be obtained in the sample without the reference. We propose the method to calculate the value of the shank angle from the shape of sample and the geometric position relationship between the sample and the detector. We compared the APT reconstruction image in this method to the image in the conventional method with the sample of Si isotope superlattice. The result is that APT 3D image by the new method was reconstructed equivalently to the image by the conventional method. [DOI: 10.1380/ejssnt.2015.235]

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The surface reconstructions and adatom kinetics on AlN(1-102) and AlN(1-101) surfaces in the presence of H₂ molecules are investigated on the basis of density-functional theory calculations. Our surface phase diagram calculations demonstrate that the H-incorporated surfaces are invariably stable over the wide range of H₂ pressure. We find that under the growth condition the adsorption energy of Al adatom on AlN(1-102) surface is much larger than that on AlN(1-101) surface. Furthermore, we find that the diffusion behavior of Al adatom on AlN(1-101) surface is significantly influenced by the presence of hydrogen. These results suggest that impact of hydrogen ambient during the metal-organic vapor-phase epitaxy growth on AlN(1-102) surface is quite different from that on AlN(1-101) surface. [DOI: 10.1380/ejssnt.2015.239]

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We investigated the crystal structure and the neutron/electron density distributions of LiMn₂O₄ in the temperature range from 150 to 573 K by the combination of Rietveld refinement and maximum entropy method (MEM). While we refined the crystal structure of LiMn₂O₄ with the space group Fddd from 150 to 240 K, we refined that with the space group, Fd-3m from 270 to 573 K. The electron density distribution which was estimated by MEM applied to X-ray diffraction, suggested that the electrons diffuse through the Mn–O sites and O–O sites at room temperature. On the other hand, the nuclear density distribution which was estimated by MEM applied to neutron diffraction, indicated that the Li atoms diffuse through 8b and 16d sites in LiMn₂O₄ with space group, Fd-3m. [DOI: 10.1380/ejssnt.2015.247]

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Using low energy electron microscopy, diffraction and x-ray photoemission electron microscopy, we study the phase separation in an Fe-Ni alloy film on W(110) at around 30 at.%Ni and at monolayer thickness. At high temperature, the monolayer-thick alloy is shown to transform into a biphase with submicron regions of different surface density exhibiting (1×1) and (1×8) structures. The former is pseudomorphic to the bcc substrate, whereas the latter is a slightly-distorted hexagonal adlayer lattice reminiscent of an fcc(111) monolayer. The stoichiometries of the two monolayer phases are Fe_0.85Ni_0.15 and Fe_0.58Ni_0.42 in laterally resolved x-ray photoemission microscopy measurements, with the bcc phase rich in Fe compared to the fcc one. This heterogeneous surface can be viewed as the two-dimensional limit of the bcc-fcc phase separation observed in thick films and in bulk Fe–Ni near the same composition. The length scale associated with the lateral heterogeneity in the monolayer film is much larger than the one observed in bulk alloys, suggesting that surface transport is the key mechanism in the kinetics of the phase separation process. [DOI: 10.1380/ejssnt.2015.256]

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We have compared positron-annihilation-induced ion desorption from clean and contaminated TiO₂ surfaces. While O⁺ ions from the clean surface were detected, H⁺ ion desorption was observed for the contaminated surface. These results indicate that positron-stimulated desorption is sensitive to changes in the surface environment. [DOI: 10.1380/ejssnt.2015.261]

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Graphene has attracted much attention due to its many unique properties and potential applications. It is considered that a chemical vapor deposition (CVD) method is a promising for growth method of graphene. We have examined growth characteristics of graphene by means of a low-pressure alcohol catalytic CVD (LP-ACCVD) method. Here nozzle gas injection is used to supply carbon source gas to a substrate. This method enables efficient supply of carbon source gas to a substrate for the growth of graphene. Therefore, an efficient growth and lowering of the growth temperature of graphene is expected. [DOI: 10.1380/ejssnt.2015.265]

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During deposition of Ga atoms on a Si(111) vicinal face, a step on the vicinal face shows a comb-like pattern. Keeping the formation of comb-like pattern in mind, we carry out phase field simulations, in which a linear adatom source advances in front of a step. The comb-like pattern consisting of straight finger-like intrusions is formed when the source velocity is smaller than a critical value determined by the step anisotropy. Initially, the straight step is unstable and step wandering is induced by the asymmetry of the surface diffusion field. The amplitude of step fluctuations increases with time and an array of short intrusions is formed. Shorter intrusions cannot catch sufficient adatoms, so that coarsening of the pattern occurs. When the adatom source moves slowly, the intrusions grow long and the step shows a regular comb-like pattern. By the coarsening, the distance between intrusions is several times larger than the initial value. The pattern is metastable for a rapid change in the source velocity. When the adatom source moves fast, the intrusions cannot keep up with the adatom source and an irregular pattern is formed. When the strength of crystal anisotropy is weak, splitting of the tips of intrusions frequently occurs and the step shows an irregular seaweed-like pattern. With a strong crystal anisotropy, the step shows a dendrite pattern. [DOI: 10.1380/ejssnt.2015.269]

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We have analyzed the narrow components in the positron annihilation angular correlation spectra of stage-2 graphite-potassium intercalation by using the topological charge density of the skyrmion-like soliton, and have discussed the energy loss rate for low-energy positrons through “topological quasi-positronium” effect. [DOI: 10.1380/ejssnt.2015.275]

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A novel nanofabrication technique, namely three-dimensional (3D) nanotemplate pulsed laser deposition, that can typically be useful for metal oxides has been developed by combining inclined pulsed laser deposition with a 3D nanotemplate prepared by nanoimprint lithography. This method enables the production of size-adjustable and extremely small functional oxide nanostructures with a high packing density over a large area, with high controllability of their shape, location, and alignment. We report various 3D functional metal oxide nanostructures, such as a luminescent ZnO nanobox structure, a ferromagnetic semiconductor (Fe,Zn)₃O₄ nanobox structure, an (Fe,Mn)₃O₄ epitaxial nanowall wire structure, and an in-plane metal-oxide-semiconductor hetero epitaxial nanowire structure. These nanostructures should be good candidates for optoelectronic, spintronic, and electronic nanoscale device applications. [DOI: 10.1380/ejssnt.2015.279]

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The Li distribution in positive electrode material (LiCoO₂) was observed after a charge-discharge cycling test by analytical transmission electron microscopy (TEM). The electron energy-loss spectroscopy (EELS) imaging method revealed an inhomogeneous Li distribution in the LiCoO₂ particles after the charge-discharge cycling test. Using the alternating least-squares (ALS) method for the data matrix of the EELS spectra, we obtained LiCoO₂ and Li-poor LiCoO₂ spectra from the LiCoO₂ particles. Around the degraded LiCoO₂ particles, Co₃O₄ and fluoride components were detected. It is suggested that inhomogeneous electrochemical reactions are one cause of LiCoO₂ and electrolyte degradation. [DOI: 10.1380/ejssnt.2015.284]

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We report the comparative studies on structural, mechanical and corrosion properties of TiAlV/SiN, TiAlV/SiN/graphene and Ti/graphene/SiN coatings. The deposited silicon nitride thin film and silicon nitride/graphene coatings systems were crack free, exhibited good adherence to the substrate, no discontinuous of the thin films was observed and the surface morphology was homogeneous. The silicon nitride thin film deposited on graphene monolayer in graphene/silicon nitride coating system, was pilling off and had poor adhesion to the graphene surface. Graphene transferred on titanium alloy surface and silicon nitride thin film surface was a single layer without defects. The hardness of silicon nitride thin film was ca. 22.4 GPa, SiN/graphene coatings system was equal 23.0 GPa and graphene/SiN coatings system was equal 22.2 GPa, showing that graphene monolayer has no affect on surface hardness of silicon nitride thin film, but at the same time it causes the decrease in the electrochemical activity of the system. The best corrosion resistance has the sample Ti6Al4V coated with SiN/graphene coatings system. This sample retains the most stable mechanical and structural parameters during corrosion process. The SiN/graphene coatings system greatly improve the mechanical and corrosion properties of examined titanium alloy surface. [DOI: 10.1380/ejssnt.2015.289]

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Carbon nanotubes filled with iron nanowires (Fe@CNTs) show magnetic anisotropy because of the high aspect ratio of the nanowires and are expected to find numerous applications such as magnetic recording media, probes for scanning force microscopy and medical treatment for cancer (hyperthermia). These applications require precise control of Fe@CNT growth. This growth depends on the condition of the substrate surface on which the CNTs are grown. In this study, Fe@CNTs were synthesized by thermal chemical vapor deposition on various thin metal films (Fe, Ni, Co, Al, Pt, Ti, or Mo) deposited on SiO₂/Si(100) substrates using ferrocene as a precursor, and their growth characteristics were investigated. The growth clearly depends on the metal species incorporated in the thin films. Magnetic properties correlated with growth morphologies. Therefore, the appropriate selection of an underlayer is important for controlling magnetic characteristics of Fe@CNTs. [DOI: 10.1380/ejssnt.2015.295]

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Interfacial water among silica particles were measured on silica colloid suspensions (0–31.1 vol.%) by transmission infrared micro-spectroscopy. The difference absorption index k spectra from the pure water of silica colloid suspensions with varying volume fractions have residual components in the O–H stretching region: the 3060 cm^-1 component increased linearly with the silica volume fraction, while the 3620 cm^-1 component increased and the 3380 cm^-1 component decreased with much less linearity. The 3060 and 3620 cm^-1 components are considered to be characteristic to the surface silanol and interfacial water and affected by overlapping diffuse electrical double layers among silica particles. [DOI: 10.1380/ejssnt.2015.301]

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We measured element specific magnetization curves for graphene/Fe/Ni(111) with a intercalated monolayer of Fe, obtained from external magnetic field dependence of X-ray absorption at Fe and Ni L₃ edges. In-plane magnetic anisotropy was clearly confirmed in both Fe and Ni magnetic sites and the strong ferromagnetic coupling of the Fe spins with the Ni spins were found at the interface. A detailed analysis of X-ray magnetic circular dichroism (XMCD) spectra leads to significant values of in-plane and out-of-plane orbital magnetic moment at the Fe site, whose anisotropy is vanishingly small. [DOI: 10.1380/ejssnt.2015.312]

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We describe two different ways to spin resolved measurements of charge delocalization times by resonant photoemission. The first approach is based on spin selective population of the core-to-bound resonance, and the second on spin resolved detection of the emitted decay electrons. Whereas the first method requires distinct electronic properties of the material under investigation, no such limitations exist for the second approach. In particular, it can be used for studies of organic materials containing the light elements of the second row of the periodic table. [DOI: 10.1380/ejssnt.2015.317]

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We carried out the X-ray diffraction studies on the crystal structure and electron density distribution of Nd-doped CeO₂ which is considered the candidate material as an electrolyte for solid oxide fuel cell by the combination of Rietveld refinement and maximum entropy method. We determined those crystal structural parameters with the space group, Fm-3m, which is the same as pure CeO₂. The Ce and Nd ions randomly occupied the 4a site and Oion preferentially occupied the 8c site in Nd_xCe_1−xO_2−δ. We observed the distribution of the electron conduction pathway through the 4a-8c and 8c-8c sites. [DOI: 10.1380/ejssnt.2015.339]

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The hydrogen absorption behavior of the Pd NPs has been investigated by the noble techniques. The Pd NPs with the clean surface have been fabricated by the gas evaporation method. The P-C isotherm of the hydrogen absorption of the Pd NPs has been obtained using the QCM without the exposure to the air. The P-C isotherms have shown the clear size dependent absorption behavior for the Pd NPs. Further absorption and desorption cycles decrease the solubility of H signicantly in the Pd NPs. [DOI: 10.1380/ejssnt.2015.343]

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Graphene growth on a carbon-doped Ni(110) substrate by surface segregation and surface precipitation has been investigated by photoelectron emission microscopy (PEEM) and micro photoelectron spectroscopy (μ-PES). Single-layer and multi-layer graphenes were found to grow on the substrate with anisotropic shape, which indicate the strong effect on the growth from the Ni(110) substrate. Most of the surface was covered by thick multi-layer graphene when the precipitation had been made with the cooling rate 0.8°C/s, while small domains of single-layer graphene and a few-layer graphene grew on the bare Ni(110) substrate by the rapid cooling (4.1°C/s). The layer dependent work functions have been measured by μ-PES. The work functions were 4.2, 4.4 and 4.6 eV for the single, double and > 3 layers graphene on the Ni(110) substrate, respectively. The μ-PES measurement with He-I reveals the shift of the final state peak characteristic to graphite or graphene depending on the number of layers. [DOI: 10.1380/ejssnt.2015.347]

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Photo-induced deformation of amorphous carbon nitride (a-CN_x) thin films was observed under visible light irradiation. This phenomenon shows the energy conversion of photon energy to mechanical energy. The a-CN_x films were prepared on rectangular ultrathin SiO₂ substrates by reactive radio frequency magnetron sputtering method at different deposition temperatures. The graphite like films were obtained with increasing the deposition temperature. In order to evaluate the photomechanical response of a-CN_x, the time resolved bending deformation of the a-CN_x/SiO₂ specimens was measured using optical-lever technique when the incident light was turned on and off. The absolute amount of bending deformation was found to be the maximum value with the specimen deposited at 573 K. As a result of the time resolved measurement of the photomechanical response of the a-CN_x/SiO₂ specimens, all of the specimens began to be bent immediately when the light was turned on and off, and then the deformation reached to the saturation value after about 4 s. The photomechanical response speed increased with increasing the nitrogen concentration, and the graphite like specimen showed low photomechanical responsivity. [DOI: 10.1380/ejssnt.2015.352]

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We observed and claried the elemental process steps in vapor phase and on surface in metal-organic chemical vapor deposition (MOCVD) reactor by in-situ infrared absorption spectroscopy, and showed schematic diagram of the reaction steps of trimethylgalliun (TMG) and AsH₃ (arsine) as precursors. The surface reactions of TMG and AsH₃ on the orientation dependence of the substrates were just the opposite each other. In discussion, the dominant reactions and the inhibitive factors for atomic layer epitaxy (ALE) of GaAs were focused. The results lead to the ALE process which dominates the surface reaction of Ga-compound followed by the surface reaction of As-compound on (100), however no reaction of Ga-compound occurs on (111)A surface, and no reaction of AsH₃ occurs on (111)B surface. [DOI: 10.1380/ejssnt.2015.357]

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L-cysteine, one of amino acids, is well known in the bioelectronics field as a linker between proteins and metal electrodes. The interface electronic structures between L-cysteine and metals are therefore very crucial because they dominate the charge carrier injection characteristics into such biological systems. However the interface electronic structures of L-cysteine and metals have been not well understood. In this study, the electronic structures at the interfaces of sequentially deposited L-cysteine layers on the metal surfaces of Au(111), Ag(111), and Cu(111) were investigated by thickness-dependent ultraviolet photoelectron spectroscopy (UPS). At the contact regions, the electronic structures of L-cysteine revealed modification with respect to its bulk phase and significant variation depending on the substrate. The electronic structure at the interfaces including work function, secondary electron cutoff(SECO), highest occupied molecular orbital (HOMO) onset, position of an interface state, charge injection barrier, and ionization energy were estimated for each case. [DOI: 10.1380/ejssnt.2015.373]

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In order to clarify the Au-anchor site in phosphate-doped Al₂O₃ and investigate the mechanism of Au-stabilization by phosphate, density functional theory (DFT) calculations were carried out. We calculated Au atom adsorption onto three model surfaces, such as sAl₂O₃ (a stoichiometric Al₂O₃ surface), fPO–Al₂O₃ (an Al₂O₃ surface fully covered by phosphate), and pPO–Al₂O₃ (an Al₂O₃ surface partially covered by phosphate). The calculated results showed that the order of stability for Au atom adsorption onto these three model surfaces is Au/fPO-Al₂O₃ > Au/pPO-Al₂O₃ > Au/sAl₂O₃. When Au atom adsorbs to a phosphate-phosphate bridge site of fPO-Al₂O₃ surface, the stabilization of Au adsorption onto the surface is especially large (the adsorption energy of Au is −3.16 eV). This high stability of Au at the phosphate-phosphate bridge site is due to negative charge transfer from Au to Al₂O₃ surface, which makes Au–O bond more stable. Hence, we have concluded that “phosphate-phosphate bridge sites” anchor Au. [DOI: 10.1380/ejssnt.2015.380]

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Light emission from interface plasmons and molecular excitons induced by the tunneling current of a scanning tunneling microscope is theoretically investigated using the nonequilibrium Green's function method. Luminescence property of the system is found to be well interpreted in terms of superposition of two coupled modes that form due to coupling between a molecular excitonic mode and an interface plasmon mode. The coupled mode whose energy is closer to the energy of the molecular excitonic mode (the interface plasmon mode) leads to a sharp (broad) peak structure in luminescence spectra of interface plasmon. Interference between these coupled modes gives rise to suppression or enhancement of luminescence intensity depending on the energy region. Especially, in the energy region near the molecular excitonic mode, the interference leads to strong suppression of luminescence from interface plasmons. Thus novel aspects of interpretation of the luminescence spectra of the system are obtained by using the analytical approach presented here. [DOI: 10.1380/ejssnt.2015.385]

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The hercynite cycle is one of the most efficient means of generating hydrogen, which is achieved by repetition of a cycle of two steps, oxidation and reduction steps. To investigate the microscopic mechanism of the oxidation processes in the hercynite cycle, we performed first-principles molecular dynamics simulations for the reaction of a Fe₂Co(Al₂O₄)₃ cluster with water molecules. In this simulations, the adsorption and dissociation reactions of water molecules are observed on the cluster surface. The active sites of these reactions are investigated. [DOI: 10.1380/ejssnt.2015.410]

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Adsorption and electrochemical reaction of graphen oxide (GO) at an Au surface was studied by surface enhanced infrared absorption spectroscopy (SEIRAS). GO film on the Au electrode is formed within 1 min. in 0.4 mg ml^-1 of GO aqueous dispersion solution. Also, it was shown that, by applying −1.0 V vs Ag/AgCl, the epoxy group of GO was reduced in 0.4 mg ml^-1 of GO and 0.1 M NaClO₄ solution, and the reaction was irreversible within the potential region under the experimental conditions studied here. [DOI: 10.1380/ejssnt.2015.413]

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In order to clarify the chemical states of radioactive cesium sorbed in minerals such as clay, soil, sand and rock, X-ray photoelectron spectra (XPS) have been measured for cesium adsorbed on SiO₂ and Al₂O₃ (sapphire), which are major components of these minerals. Since the number of atoms in radioactive cesium (¹³⁴Cs or ¹³⁷Cs) is extremely small, total reflection XPS (TR-XPS) using synchrotron radiation was applied in order to measure trace amount of cesium. For SiO₂ surface, it was shown that ultra-trace amount of cesium down to 205 pg·cm⁻² can be detected by TR-XPS. This amount corresponds to about 400 Bq of ¹³⁷Cs (t_1/2=30.2 y). Thus it was demonstrated that the ultra-trace amount of cesium corresponding to the radioactive cesium level can be measured by TR-XPS. As to the chemical states of cesium, the binding energy of the Cs 3d_5/2 line for cesium adsorbed on SiO₂ and Al₂O₃ ranges from 725.2 eV to 725.5 eV irrespective of the adsorption conditions, suggesting that the cesium is adsorbed through weak Van-der-Waals force. While after rinsing the cesium-adsorbed SiO₂ in water, the binding energy of the Cs 3d_5/2 line shifted by 0.8 eV to higher energy side. The result indicates that the ultra-trace amount cesium remaining after rinsing is covalently bonded with the SiO₂ surface rather than ionically bonded. [DOI: 10.1380/ejssnt.2015.417]

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Synthesis of SiOC(–H) films outside generation regions using afterglow plasma under atmospheric pressure have been gaining attention because it allows deposition to complex configuration substrates with large area. We synthesized SiOC(–H) films at different oxygen gas flow rates and substrate temperatures by the atmospheric pressure plasma enhanced chemical vapor deposition method from TrMS/O₂/He gases. Substrates were placed at a working distance of 10 mm between discharge electrode and substrate surface. Plasma emission is gradually weakened with an increase in oxygen gas flow rate, and excessive introduction of oxygen into the process caused the plasma to disappear. The SiOC(–H) films were composed of a number of particles; Their large size particles lead to an increasing deposition rate and the non-dense structure of the films. As the oxygen gas flow rate increased, the particle size was larger at 100 nm and related -OH peaks strongly observed. Carbon content of SiOC(–H) films decreased from 17% to only 1.8% with an increase in substrate temperature at 140°C. In this paper, we report the characterization of SiOC(–H) films synthesized under atmospheric pressure PECVD method. [DOI: 10.1380/ejssnt.2015.445]

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We prepared silica-coated ZnO nanoparticles and evaluated the dispersibility and photoluminescent properties by comparing the properties of ZnO nanoparticle dispersion. It was confirmed that the Zeta-potential of the nanoparticles in saline was changed from 1.52 mV to −43.06 mV and the intensity of the exciton emission of ZnO was enhanced around 20 times by silica coating. These results indicated that the silica coating technique was effective for enhancing the dispersibility and controlling the fluorescence quenching of the emission of ZnO. [DOI: 10.1380/ejssnt.2015.451]

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We have conducted a pilot study of a biological filtration (BF) system for low-cost arsenic (As) removal from groundwater containing both ferrous iron (Fe(II)) and arsenic (As). Throughout the study, we have observed that arsenite (As(III)) as well as arsenate (As(V)) could be removed with this system. In conventional water treatment technologies, the preoxidation of As(III) to As(V) by oxidizing chemical is a mandatory step for As(III) removal However, such a preoxidation unit has not been used in our BF pilot unit, and hence the mechanisms of As(III) removal by BF have been of interest. Using a flow-through column reactor that simulates the actual BF pond for analysis by X-ray absorption spectroscopy (XAS), we could observe the adsorption of As(III) in water onto iron hydroxides deposited on the biological filter. The time-resolved As K-edge X-ray absorption near-edge structure (XANES) spectra were obtained when the water containing As(III) and Fe(II) was continuously fed to the reactor. An increase in the absorption intensity of the X-ray with time was clearly observed in the time-resolved spectra, indicating that the spectra represented the concentration and chemical state of As adsorbed at the solid-liquid interface of the biological filter. The XAS results also show that while the original water fed to the reactor was supposed to contain only As(III) and Fe(II), a small portion of As(III) was oxidized to As(V) in the influent line when the As(III) solution met the Fe(II) solution before flowing into the reactor. Consequently, besides As(III), As(V) probably formed by the oxidation of As(III) in the influent, was detected on the filter by XAS. The results demonstrate that, in BF, mechanisms of As(III) removal are at least partially explained by the adsorption of As(III) in the raw water to the biological filter as it is. [DOI: 10.1380/ejssnt.2015.455]

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Stratum corneum (SC), the outermost skin layer, consists of corneocytes and intercellular lipids. In this study, mechanical properties of a cultured human SC and a tape-stripped human corneocyte were examined in a glycerine solution through atomic force microscopy. A multilayered cultured human SC in the low concentration glycerin solution decreased its Young’s modulus with time. Besides the corneocyte increased its adhesion force in higher concentration of glycerin solution. [DOI: 10.1380/ejssnt.2015.461]

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Voltage-induced changes in the magnetic properties of FeCo thin films grown on a BaTiO₃ substrate are investigated by means of the X-ray magnetic circular dichroism (XMCD). The magnetization curves show different effects of the applied voltages depending on the Fe-Co compositions, which are ranging from Fe₆₇Co₃₃ to Fe₂₅Co₇₅. The XMCD spectra suggest that magnetization of the Fe₅₀Co₅₀ film at the saturation state are different between the positive and negative applied voltages, while those for other compositions have no detectable dependence on the applied voltage. The peculiar behavior for Fe₅₀Co₅₀ could be related to the abrupt change in the density of state at the Fermi level. [DOI: 10.1380/ejssnt.2015.465]

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Multi-quantum wells (MQWs) consisting of 3 or 3.5 pairs of nominally 8.8-nm-thick GaAs layers and 5.6-nmthick GaAs_0.97Bi_0.03 were grown by molecular beam epitaxy with varying the growth temperature of GaAs layers, T_GaAs, and keeping the growth temperature of the GaAsBi layers at 350°C and their Bi compositional structure and optical properties were investigated. Analysis of x-ray diffraction spectra reveals that 67% of the total Bi atoms supplied during growth of a single GaAsBi layer were segregated on the growing surface and were incorporated into the successive GaAs layer at T_GaAs = 350°C. The GaAs layers at T_GaAs = 450 and 500°C contained 17% of the Bi atoms totally supplied and 50% of them were evaporated. Almost all Bi atoms segregated during growth of GaAsBi evaporated and were not incorporated into the GaAs layer at T_GaAs = 550°C or higher. Photoluminescence (PL) spectra at 13 K shows all MQW samples have good optical quality and the MQW sample grown at T_GaAs = 550°C shows the longest wavelength emission peak at 1116 nm which is 44 nm longer than the PL wavelength for the MQW grown at T_GaAs = 350°C, even though the tremendous reduction of Bi incorporation into the GaAs layer grown at T_GaAs = 550°C. The result strongly suggests that GaAsBi/GaAs has the type II band configuration. [DOI: 10.1380/ejssnt.2015.469]

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To understand the surface damage of AlGaN film caused by plasma etching in detail, we etched AlGaN film with CF₄ and Ar plasmas. The intensity of ultraviolet (UV) light emitted from the CF₄ plasma was very weak at each gas pressure investigated. However, in the case of Ar, a certain degree of UV intensity was observed at gas pressures between 50 and 100 mTorr. The surface etched with the CF₄ plasma was as smooth as that of the as-grown film. In the case of Ar, surface roughening occurred at gas pressures between 50 and 100 mTorr. The Al/N and Ga/N ratios of the AlGaN surface etched with Ar plasma increased more significantly than those of the surface etched CF₄ plasma, as determined by X-ray photoelectron spectroscopy (XPS). The peak shape of the near-edge X-ray absorption fine structure (NEXAFS) spectra in the N-K absorption edge was broadened by the plasma etching with increasing processing-time. The broadening observed in the case of Ar etching was greater than that during CF₄ plasma etching. The observed changes in the surface morphology and crystalline structure of the AlGaN are considered to be caused by the synergistic effect of UV light irradiation from the plasma and ion bombardment of the sample surface. The changes in surface composition, surface roughening, and the disordering of the crystalline structure were found to occur within a shallow region from the surface, and did not occur in deeper regions of the sample. F atoms (ions) were found to penetrate the surface to a depth of about 10 nm in the AlGaN etched with CF₄ plasma. [DOI: 10.1380/ejssnt.2015.481]

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We demonstrate a method to clean and probe a graphene layer on copper by using cluster ions consisting of thousands of argon (Ar) atoms. Ar cluster ions colliding with a solid at kinetic energies below ∼5 eV/atom dissociate into smaller cluster ions such as Ar₂⁺ or Ar₃⁺, and the dissociation rate (ease of dissociation) depends on the physical property of the solid. We apply this phenomenon to probe a graphene layer on copper. Contaminants at the graphene surface are removed without damage to the surface by Ar cluster ion bombardment and the cleanliness of the surface is simultaneously probed by measuring the dissociation rate. This rate gradually approaches the value for a clean surface. After cleaning, the dissociation rate for pristine graphene on copper is five times lower than that for bare copper, indicating that the graphene layer acts as a buffer against the impact force of the cluster ion upon collision. Accordingly, the method can probe the quality of graphene, such as carbon coverage, by comparing the dissociation rate with that for bare copper. Furthermore, the method can probe the interface between graphene and copper, showing that the dissociation rate increases with increasing copper oxidation. The obtained experimental results are compared with simulated results obtained by molecular dynamics simulation for the collisions of an Ar cluster ion with graphene on copper. The combined results are discussed with respect to the utility of the proposed method for controlling the quality of graphene in the manufacture of electronic or mechanical devices. [DOI: 10.1380/ejssnt.2015.167]

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We examined the photometric characteristics of ultraviolet light (UV) measurements of aqueous solution and polyvinyl alcohol (PVA) film containing bromothymol blue (BTB) and diphenyliodonium salts (chloride, nitrate and trifluoromethane sulfonate). The solution and film were initially green (neutral), but were changed to yellow (acidic) by irradiation with 254 nm UV from a mercury lamp. A solution and film containing only BTB did not show the color change, which we concluded was solely induced by the acid generation from the diphenyliodonium salts. Photochemical kinetics of the UV-induced color change are discussed on the basis of experimental results; the color change proceeded obviously according to pseudo-first-order kinetics. This BTB/diphenyliodonium salt system could be used as a low-cost, mobile UV dosimeter. [DOI: 10.1380/ejssnt.2015.15]

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We used a self-organized polymer microhoneycomb structure as a template to form polyaniline structures that contain hexagonal voids. The polyaniline was synthesized in situ and adsorbed spontaneously on a polymer honeycomb structure that was immersed in the solution. Successive adsorption cycles led to thicker polyaniline coating. The characteristic honeycomb structure could be preserved during the process. Electrical measurements showed that the film resistance is the sum of contact and sheet resistance. [DOI: 10.1380/ejssnt.2015.19]

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Terbium oxide nanoparticles, TbO_x nanoparticles, were synthesized by the thermal reaction of Tb(III) complexes as a single-source precursor with acetylacetone (acac) or hexafluoroacetylacetone (hfa). Thermal decomposition processes of Tb(III) complexes for preparation of TbO_x nanoparticles were characterized by the thermogravimetric analysis (TGA). The prepared TbO_x nanoparticles were identified using XRD and TEM measurements. [DOI: 10.1380/ejssnt.2015.23]

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Series of nonanuclear Tb(III) clusters with ligands of different length of alkyl chain groups and their photophysical properties are demonstrated. The nonanuclear Tb(III) clusters (Tb₉ clusters) are composed of nine oxygen-bridged Tb(III) ions and sixteen alkyl salicylate ligands, where alkyl chain are ethyl (Tb₉-Et), propyl (Tb₉-Pr), butyl (Tb₉-Bu), and hexyl (Tb₉-Hex) groups. The luminescence properties of the Tb₉ clusters are characterized by absorption spectra, emission quantum yields, and emission lifetimes. The radiative (k_r) and nonradiative (k_nr) rate constants were calculated from their photophysical properties. Tb₉-Hex have shown the highest k_r (859 s^-1) and lowest k_nr (137 s^-1), owing to the tight packing due to CH-π interaction by long alkyl chains. [DOI: 10.1380/ejssnt.2015.27]

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The chiroptical properties of nonanuclear Tb(III) clusters are reported. The nonanuclear Tb(III) clusters are composed of nine Tb(III) ions, ten μ-OH parts, and sixteen chiral organic ligands, (±)-bornyl salicylate. Their chiroptical properties were estimated by circular dichroism (CD) and circularly polarized luminescence (CPL). Their electronic structures were calculated using TD-DFT (B3LYP/6-31G(d)) method. [DOI: 10.1380/ejssnt.2015.31]

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Europium ions were doped in silica glass matrix with a sol-gel method as well as Al co-dopant. The samples densified at 1050°C showed bright blue emission under UV illuminations. Lifetime of the luminescence was about 1 μs and did not depend on Al concentration, indicating that europium existed as divalent form at proximate positions to aluminum ions. [DOI: 10.1380/ejssnt.2015.51]

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Investigation for the operation mechanism in writing and reading processes are necessary in order to realize practical 3D devices with azo-carbazole dyes which are promising candidates for real-time 3D displays. We made dynamical studies of four-wave mixing and two-beam coupling for dyes 3-[(4-nitrophenyl)azo]-9H-calbazole-9-ethanol (NACzEtOH) and Disperse Red (DR1) doped in a polymer and investigated their dependence on dye concentration. Results indicated the important roles of birefringence on the holographic response and stable but erasable characteristics of the gratings in the azo-carbazole. [DOI: 10.1380/ejssnt.2015.69]

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Oxygen is an indispensable resource for action of humans or autonomous underwater vehicles in water. However, it is limited in the present situation because of a capacity of O₂ cylinders. In nature, there are some insects, which utilize superhydrophobic hair structures as physical gills, semipermanently living in water. We focused on this physical gill of the plastron and prepared artificial plastrons by using self-organized honeycomb-patterned films. As result, durable honeycomb-patterned films resisting water pressure were obtained, and O₂ transferred from air to water though the films. This phenomenon suggests the honeycomb-patterned films showed possibility of use as artificial plastrons. [DOI: 10.1380/ejssnt.2015.90]

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Polyethylenimine (PEI) is one of the most effective polymers for non-viral gene delivery; however, the mechanism by which DNA binds to PEI remains unclear. In this study, the reaction rate between DNA and PEI was determined using quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). The association rate constant was determined as 0.8–1 s^–1 mM^–1, and the dissociation rate constant was found to be 1–2 ×10^–3 s^–1. The data obtained from these measurements could be explained using the two-site fitting model. One proposed binding site for the DNA was the PEI; however, the DNA could also have bound directly to the gold surfaces of the sensor devices. Furthermore, the suitability of this two-site model for DNA binding was evaluated in this study. [DOI: 10.1380/ejssnt.2015.99]

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It has been theoretically predicted that spherical particles added to the smectic phase formed by rod-like particles segregate between the smetic layers and significantly enhance the stability of the smectic phase due to an entropic effect based on the steric repulsion between the particles, which is referred to as the depletion effect. In this study, we describe the first experimental verification of the theoretical prediction, in which the binary mixtures of the rod-like polymer, poly[n-decyl-(S)-2-methylbutylsilane] (PDMS), with narrow molecular weight distributions, and a spherical branched alkane, squalane, were investigated by synchrotron radiation small- and wide-angle X-ray scattering (SR-SAXS and SR-WAXS) and atomic force microscopy (AFM) observations and found to reproduce the predicted segregation between the smectic layers. [DOI: 10.1380/ejssnt.2015.121]

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The determination of electronic states of single-walled carbon nanotubes (SWNTs) has been a central issue in nanoscience of carbon nanotubes. We have established an in situ photoluminescence (PL) spectroelectrochemistry to determine the electronic properties of the SWNTs. This review article focuses on the fundamentals of the in situ PL spectroelectrochmical method to determine electrochemical potentials of isolated SWNTs and microenviromental effects on the electronic states of the SWNTs, electronic states of SWNTs with a single chirality, and empirical prediction for the electronic potentials of the SWNTs. Such electronic state determination is important for detailed understanding about fundamental properties of the SWNTs and their applications, especially in electronic device applications of the nanotubes. [DOI: 10.1380/ejssnt.2015.179]

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Polymer microparticles that have pollen-like surface structures can be prepared by the evaporation of an oil-in-water emulsion. Here, polystyrene, polysulfone and PMMA was dissolved in ethyl acetate (the oil phase) and mixtures of those were emulgated in aqueous solutions of various emilsiers. The polymer particles show surface structures, and we found that polysulfone makes hemispherical protrusions in various mixtures with polystyrene or PMMA. [DOI: 10.1380/ejssnt.2015.204]

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The luminescent nanoparticles with Eu(III) ions are reported. Standard nanoparticles are prepared by the reaction of europium chloride with dpp (diphenylphospinic acid) joint ligands. The size-controlled nanoparticles are synthesized by the reaction of Eu(hfa)₃(H₂O)₂ (hfa: hexafluoroacetylacetonate) with bidentate dpbp ligands (dpbp: 4,4'-bis(diphenylphosphoryl)biphenyl) and monodentate ligands (TPPO: triphenylphosphine oxide). Their particle sizes were characterized using TEM and dynamic light scattering (DLS) measurements. Their luminescence properties were estimated by the emission spectra and lifetimes. [DOI: 10.1380/ejssnt.2015.219]

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Collagen fiber orientation in the femur of chronic kidney disease (CKD) rats was determined using Fourier transform infrared (FTIR) imaging with a wire grid polarizer in order to characterize bone quality in CKD. Eleven-week-old male rats underwent 5/6 nephrectomy (Nx) to replicate CKD. These CDK rats, as well as sham-operated rats (sham), were kept for 16 weeks. After sacrifice, femurs in the sham and CKD rats were removed and embedded in PMMA. Longitudinal sections (∼3 μm) of the femurs were prepared for FTIR imaging. IR dichroism images were calculated from the FTIR images obtained using two polarized IR beams (0° and 90°). The IR dichroism images of the collagen fibers in the CKD rat femurs indicated that the collagen fibers in the cortical bone were aligned longitudinally, and the degree of collagen fiber orientation was decreased in the metaphysis compared to that in the diaphysis. The carbonate-to-phosphate ratio in the hydroxyapatite was reduced in both the cortical bone and trabecular bone of the CKD rat femurs. In the cortical bone, reductions in the carbonate-to-phosphate ratio and collagen fiber orientation were particularly evident in the metaphysis in the CKD rats. [DOI: 10.1380/ejssnt.2015.244]

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Various kinds of carbon nanotube-based and graphene-based nanomaterials are considered as future materials for electronic devices due to their outstanding properties. This review paper reports tip-enhanced Raman scattering (TERS) studies of polymer nanocomposites containing carbon nanomaterials and graphenes. TERS is an emerging spectroscopic tool that combines scanning probe microscopy and Raman spectroscopy. Compared with normal Raman spectroscopy, TERS has much better spatial resolution and sensitivity. The usefulness of TERS technique in studying structure and interactions of nanomaterials is demonstrated by introducing four TERS studies. [DOI: 10.1380/ejssnt.2015.329]

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On July 30th 2015, the Editor-in-Chief sent a letter to the corresponding author of the above-mentioned manuscript [1] about the result of survey by the Editorial Committee of e-J. Surf. Sci. Nanotech. According to the letter, the Committee concluded that the above-mentioned manuscript resembles the paper published in another journal [2] too much. As a result of this report, all of the authors of the above-mentioned manuscript have agreed to a complete retraction of the paper.

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