Salt bath nitrocarburizing effects on usefulness and performance of a new grade hot working tool steel close to as either chromium AISI H11/H13 are investigated. A continuous two-step treatment is performed, consisting in hardening sequence (i.e. austenization-1050°/15 min, quenching-oil medium and twice tempering-500 and 600°C/2 h) followed by a salt bath nitrocarburizing process at 580°C for various processing times. Prior treatments yield a reliable tempered martensitic microstructure without bainite, in which are embedded complex carbides without any retained austenite content, achieving satisfactory hardness value of 53HRC. Subsequent thermochemical treatments allow relative relevant properties such as surface hardness and wear behavior through formed layers that are characterized by their basic properties (i.e. thickness, formed phases, hardness distributions and redistribution of alloying elements in the nitrocarburized layers). Based on in-house experimental data, it can be outlined that salt bath nitrocarburizing process is suitable for improving surfaces characteristics of the as-studied treated material, in a shorter time with minimal cost compared to other similar processes. Metallurgical evaluations are carried out using metallographic techniques, optical and scanning electron microscopy equipped with an energy-dispersive X-Ray spectrometer as well as X-ray diffraction techniques. Mechanical properties are achieved mainly by standard hardness and wear tests. [DOI: 10.1380/ejssnt.2012.1]

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We fabricated nanometer-size pyramids with three {211} -facet sides (nanopyramids) on blunt W tip and observed their atomic structures by field ion microscopy (FIM). The blunt W tip was preliminary subjected to remolding treatment in order to sharpen its end. Owing to the atomic resolution of FIM, we found that the {211} and {110} planes faceted markedly as a result of the remolding treatment and clearly detected the neighboring {211} and {110} planes were separated by a monoatomic chain along the <111> direction. In addition, the (111) plane was raised and narrowed owing to the faceting of the three surrounding {211} planes. Dimension of the narrowed (111) plane was about 3 nm. By using the surface of the remolded-tip end as a substrate, we grew the nanopyramid by depositing Pd atoms and elevating the sample temperature to 1000 K. The FIM observation indicated typical signs for the nanopyramid growth such as markedly-faceted {211} planes, monoatomic linear chains for the pyramid ridge, and extremely narrow top of the pyramid. In this study, the top was the third layer of the ideal nanopyramid counting from the top. Along with previous field emission data [E. Rokuta, T. Nakagawa, H. Murata, S. Fujita, H. Shimoyama, and C. Oshima, Jpn. J. Appl. Phys. 50, 115001 (2011).], the remolding treatment was proven to be useful for the nanopyramid growth on the blunt end of the W tip. [DOI: 10.1380/ejssnt.2012.12]

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We evaluated the fixed charge (Q_f) and the interface state density (D_it) from the capacitance—voltage (C—V) measurement before and after rapid thermal cycle annealing (RTCA) using p-type silicon in which the passivation was performed with aluminum oxide (Al₂O₃) film by atomic layer deposition (ALD). From C—V measurement we obtained the surface potential (V_S), accumulation and depletion width, and as a result, energy band diagrams were produced. It was determined that a barrier height of approximately 100 mV was induced by fixed negative charges in the Al₂O₃ layer near the interface to the p-type Si substrate. The field effect of the Al₂O₃ passivation layer created by RTCA strongly remains without depending on the gate voltage (V_G). [DOI: 10.1380/ejssnt.2012.22]

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The interaction of nanoclays with polar polymers is receiving greater interest because the nanoclay significantly improves the thermal stability of the composites; however, since most polar polymers are bio-based, their mechanical properties and processing are of relatively lower standard than the oil-based polymers. We investigated a commercially relevant polymer with varying degree of polarity (poly(ethylene vinyl acetate) copolymer (EVA) with varying polarity due to varying vinyl acetate content (9, 18 and 28%)) and its interaction with organo-modified nanoclay filler (CloisiteR C15A and C30B). Specifically, we studied the crystallization kinetics and the relative dispersion of the nanoclays within the composites using modulated differential scanning calorimetry (DSC) and X-ray Diffraction techniques. Transmission Electron Microscopy results show that clay platelets have increasing tendency to be dispersed as the polarity of the matrix is increased; however, the overall matrix crystallinity remains largely unmodified due to nanoclays but the overall morphology was significantly modified in a way that there was an increase in the ‘rigid-amorphous’ phase. Using Avrami kinetics, we demonstrate that nanoclays play a significant role in the mechanism of growth of crystals and crystalline distribution for EVA polymer and the analysis could be used to compare processing of composites for optimizing mechanical properties for a range of applications in the flexible packaging industry. [DOI: 10.1380/ejssnt.2012.79]

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BiOCl sheets with tetragonal structure have been succesfully synthesized via a hydrothermal route using BiCl₃ as the starting materials. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and photoluminescence (PL) spectrum. The diameter and thickness of the BiOCl sheets can be adjusted by controlling the hydrothermal temperature and growth time. And BiOCl nanosheets can be obtained. PL spectrum of the BiOCl sheets shows blue light and green light emission, indicating potential application in optical devices. [DOI: 10.1380/ejssnt.2012.161]

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We have performed density-functional theory calculations to investigate the alignment of gallium (Ga) and nitrogen (N) atoms at m-plane wurtzite GaN/ZnO hetero-interfaces. The potential energy surface (PES) for Ga adatom and N adatom on the clean m-plane ZnO(1010) and m-plane ZnO(1010) with co-adsorbed Ga and N adatoms are calculated. The most stable alignments in each calculation for PES show us that the hetero-interface structure between GaN and ZnO changes depending on the growth condition. Under the Ga-rich condition, the stable site of N adatom changes because of the self-surfactant effect of the Ga atoms. Under the stoichiometric condition, the stripe structure will be obtained along [0001] direction and the self-surfactant effect of Ga atoms dose not work. Under the N-rich condition, the N adatom forms N₂ molecule with the N on the surface and desorb from the surface. We found the condition for growing up an ideal crystal in this hetero-interface. [DOI: 10.1380/ejssnt.2012.221]

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In this study, contact angle measurements and an infrared p-polarized multiple-angle incidence resolution spectrometry (p-MAIRS) technique were performed on MgO(100) and quartz substrates. The contact angle and IR spectra of the in-plane and out-of-plane vibration modes depended on the cleaning methods. The surface of the as-received substrates was contaminated in MgO(100) and quartz substrates. As determined by contact angle and p-MAIR spectra analysis, plasma treatment resulted in a relatively clean and superhydrophilic surface under atmospheric conditions. [DOI: 10.1380/ejssnt.2012.229]

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In this paper, the formation of microscopic polystyrene/poly(methyl methacrylate) Janus particles by using environmentally benign solvents and surface active agents is presented. Janus particles are formed by the rapid polymer phase separation that occurs when an oil-in-water suspension is allowed to dry. Biodegradable or bio-inert organic solvents and surface active agents are used. These solvents affect the particle morphology, which is studied in detail. The environmentally friendly solvent ethyl acetate can replace the more commonly used toluene for the preparation of Janus particles. Confocal Raman microscopy is used to visualize and analyze the phase separated Janus particles. Results indicate that the polystyrene hemisphere as minor component within the particle is covered with a thin PMMA layer on its surface. [DOI: 10.1380/ejssnt.2012.360]

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We report herein on the fabrication of carbonaceous material produced from cotton treated with Tricresyl phosphate (TCP) for fireproofing and its evaluation for adsorbing Methylene blue (MB). We prepared two carbonaceous materials: cotton calcined at 900°C (CT900) and cotton calcined at 900°C with TCP (F-CT900). These materials were evaluated in terms of their scanning electron microscope images, specific surface area, pore volume, mean pore diameter, and solution pH. We found that the specific surface area of F-CT900 (1492 m²/g) is greater than that of CT900 (910 m²/g), and that the mean pore diameter of F-CT900 (2.41 Å) is smaller than that of CT900 (9.09 Å). The adsorption of MB onto CT900 and F-CT900 reached equilibrium within 5 h. We fitted the experimental data with the pseudo-second-order model and obtained correlation coefficients between 0.993 and 0.999. We found that more MB adsorbed onto F-CT900 (about 650 mg/g) than onto CT900 (about 350 mg/g). We also fitted these experimental data with both the Freundlich and Langmuir equations. Thus, carbonaceous material for MB removal could be produced from fireproofed cotton, and it is useful for the purification of dye solution systems. [DOI: 10.1380/ejssnt.2012.374]

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Temperature dependence of the exciton in a Cd_1-xoutMn_xoutTe/Cd_1-xinMn_xinTe/Cd_1-xoutMn_xoutTe strained quantum well is investigated for various Mn content. Spin polaronic shifts are estimated using mean field theory for different Mn concentration and the well sizes. Calculations are performed for various Mn ion content in a Cd_1-xMn_xTe material in which the strong built-in electric field due to piezoelectric polarizations are included. A theoretical study of diluted magnetic semiconductors treating local sp—d exchange interaction J between the itinerant carriers and the Mn electrons are treated within a realistic band structure. The temperature dependent optical absorption and the refractive index changes as a function of normalized photon energy with various Mn ion content are analyzed. Our results show that the occurred red shifts of the absorption resonant peak due to the effect of temperature give the information about the variation of two energy levels in the quantum well. The optical absorption coefficients and the refractive index changes strongly depend on the incident optical intensity, the temperature effect and the Mn content. [DOI: 10.1380/ejssnt.2012.388]

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A dual-probe scanning near-field optical microscope was developed. The probe pair positioning was carried out using conventional microscopy with an accuracy beyond the diffraction limit. The distance dependence of the inter-probe light transfer was measured to show the strong far-field influences. A dual-probe observation of an optical grating was performed. Gained two signals contained various information from the probe-pair and the sample. A method to process the two signals was suggested and discussed using three dimensional finite-difference time-domain simulations. Two independent signals specific to each probe were shown to be extracted by the procedure. [DOI: 10.1380/ejssnt.2012.426]

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Diamond made AFM probe exhibits a long life time as diamond has ultrahigh hardness, ultra high tensile strength and high wear resistance. For the ultra fine machining of diamond tip, focused ion beam (FIB) machining is being widely used but the process is very slow due to one by one processing and ripples are formed on the processed surface. Moreover, the irradiation damage and machining cost are significantly high. Compared to FIB machining, low energy broad ion beam machining (BIBM) is better suitable for the mass fabrication of AFM tips. In this paper, we presented a two stage BIBM process using 1-3 keV O⁺/O₂⁺ ion beam for the mass fabrication of ultra smooth and sharp AFM nano-tips from single crystal diamond rods. In order to suppress the ripple formation on the processed diamond tip, the sample was rotated during machining process. In our proposed method, around 100 ultra smooth and sharp AFM nano tips with the apex angle of 50° and an average tip diameter of 22 nm can be simultaneously fabricated in just 1.5 hour. Moreover, the irradiation damage of the processed tip is also very low due to low energy ion beam machining and chemical etching of the amorphous carbon by the oxygen ions. A simulation model is developed to predict the profile change of diamond tip by low energy oxygen ion beam machining. At last, the mechanisms of fine sharpening and ultra smoothening of the diamond tips are discussed with the help of Witcomb formula and Bradley-Harper (BH) model. [DOI: 10.1380/ejssnt.2012.447]

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Shave-off profiling with nano-beam SIMS achieves the highly precise depth profiling with nanometer-scaled depth resolution by utilizing FIB micro-machining process to provide depth profile. This method has its own features: absolute depth scale, pin point depth profiling and application to rough surface and/or hetero interface. However, the discussion of the sputtering mechanism in shave-off profiling is still insufficient because shave-off scan mode has distinctive position of the primary ion beam against the sample. In this study, the sputtering yield and the mixing effects within the primary ion dose amount of up to 1.0×10¹⁶ ions/cm² under shave-off condition were investigated using molecular dynamics simulations. These results were compared with those of under conventional raster scan mode. In addition, the ejected region of sputtered atoms was investigated. As a result, it was proved that shave-off scan mode has high sputtering yield and low mixing effects. Moreover, the relationship between the sputtering phenomenon and the atomic displacement under shave-off scan mode was demonstrated. [DOI: 10.1380/ejssnt.2012.463]

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Conventional grinding and polishing mechanisms for fabricating ultra-sharp diamond knives often cause subsurface damage and micro-chipping at the cutting edge. Compared to mechanical methods, ion beam machining (IBM) is considered more suitable for nano-scale machining of diamond materials. But the problems associated with IBM are facet formation, ripples formation and high irradiation damage. In order to overcome all theses problems, we proposed a 500 eV O⁺/O₂⁺ ion beam machining for the fabrication of smooth and ultra-sharp diamond knives from mechanically coarse finished samples. In our method, the knives are irradiated at tilted condition to avoid facet formation at the cutting edge. To suppress ripples formation and obtain isotropic smoothening of the surface, the stage is simultaneously rotated around the axis of ion beam incidence. To reduce the irradiation damage, a low energy reactive ion species is used in this method. A simulation model is developed to predict the profile change of knives at different tilted conditions and then compared with experimentally obtained results. We achieved sharpening down of the apex angle from 90° to 68° and from 60° to 48° by 5 hrs of machining. We also successfully reduced down the diameter of tip from 5 μm to lower than 60 nm with an average cutting edge irregularity 20-40 nm. [DOI: 10.1380/ejssnt.2012.467]

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Carbonaceous materials produced from coffee ground (virgin CG, CG600, CG800, and CG1000) were prepared. Specific surface areas, mean pore diameters, pore volumes, and SEM images of the CGs were investigated. The specific surface areas were in the order CG1000 (23.5 m²/g) < CG800 (31.5 m²/g) < CG600 (52.6 m²/g), and the mean pore diameters were in the order CG600 (77.0 Å) < CG800 (139.3 Å) < CG1000 (273.8 Å). The amounts of nitrate, nitrite, and fluoride ions adsorbed in a single solution system were greater than the amounts adsorbed in a ternary solution system; this indicated that the ions were competitively adsorbed onto the CGs in the complex solution system. Moreover, the adsorption mechanism was ion exchange with chloride ion onto the CGs in a 1:1 ratio. Adsorption isotherms were fitted to both the Freundlich equation and the Langmuir equation. The amounts adsorbed increased with increasing temperature. The adsorption affinities onto the CGs were in the order nitrate ion < nitrite ion < fluoride ion. The most suitable breakthrough curve conditions were Space velocity: 4.24 1/h and Linear velocity: 0.38 m/h. Thus, carbonaceous materials produced from coffee grounds were useful for the adsorption of nitrate, nitrite, and fluoride ions in a ternary solution system. [DOI: 10.1380/ejssnt.2012.493]

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In this study, powdered boehmite (AlO(OH)) was compressed to obtain a granulated form without using a binder. The granulated product was assessed via SEM imagery, TG-DTA, specific surface area, surface pH, and hydroxyl groups. The SEM images showed that powdered BE could be successfully granulated by compression without binders. TG-DTA showed that dehydration of adhesion and bound water occurred at 96.0 and 394.6°C, respectively. The amount of phosphate adsorbed onto granulated boehmite increased with temperature, indicating a chemisorption mechanism. Moreover, equilibrium adsorption was reached within 20-24 h. Adsorption kinetics data was fitted to the pseudo-second-order model. [DOI: 10.1380/ejssnt.2012.518]

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Temperature dependence of oxide growth kinetics on the Si(111)7×7 surface has been investigated by ultraviolet photoelectron spectroscopy. The amount of adsorbed oxygen on the Si surface during oxidation can be obtained from the O 2p spectra, which showed that the amount of oxygen increased with temperature below 600°C. It was found that the results cannot be described by the dual-oxide-species model for Langmuir-type adsorption in which adsorbed oxygen hardly moves on the surface. Therefore, we propose a new reaction model in which the migration and agglomeration of metastable oxygen on the surface should be considered. By studying the results of work function, we concluded that more adsorbed oxygen on the surface may incorporate into the back bond and a larger amount of defects can be generated at the Si/SiO₂ interface at higher temperature. [DOI: 10.1380/ejssnt.2012.525]

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Calcium sulfate and calcium vanadate nanostructures have been synthesized by a hydrothermal route using calcium sulfate and sodium vanadate as the raw materials. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectrum. XRD and SEM observation show that the products are composed of calcium sulfate nanosheets with orhorhombic CaSO₄ phase and calcium vanadate nanorods with tetragonal CaV₄O₉ phase. The size and morphology of the products can be adjusted by controlling the hydrothermal conditions and raw materials. The size of calcium sulfate nanosheets and calcium vanadate nanorods increases obviously with increasing the hydrothermal temperature and reaction time. The formation process of the calcium sulfate and calcium vanadate nanostructures is also discussed. [DOI: 10.1380/ejssnt.2012.585]

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The feasibility of the high-resolution medium energy elastic recoil detection analysis using a sector type magnetic spectrometer was studied for the depth profiling of boron in silicon. Two different methods were examined to reject the scattered probe ions. One is installation of a thin mylar foil in front of the focal plane detector of the spectrometer. The other is the use of He⁺ ions as a probe. The pros and cons of these two methods as well as high-resolution RBS were discussed based on the experimental results. It was demonstrated that the use of He⁺ ions as a probe is the best method among these three methods. [DOI: 10.1380/ejssnt.2012.655]

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We have constructed an ultrahigh vacuum system in which surface conductivity is measured in situ by micro-four-point probe method down to 0.8 K, combined with conventional surface preparation/analysis capability. In order to reduce the data scattering due to changes of the probe spacing, we have employed a dual configuration method in which the combinations with current/voltage probes are switched. The surface-state superconductivity of Si(111)-√7 × √3-In surface superstructure was confirmed with the critical temperature of 2.8 K. The critical magnetic field was 0.3-0.4 T in the surface-normal direction. [DOI: 10.1380/ejssnt.2012.400]

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Nanoclusters of Ge, such as hut clusters and pyramidal clusters, were grown on Si(001) substrates and evaluated by surface electron diffraction methods such as reflection high-energy electron diffraction (RHEED) and low-energy electron diffraction (LEED). Observations of the same sample by both RHEED and LEED were carried out for the first time. The diffraction spots had a characteristic shape and intensity distribution depending on the morphology of the clusters. The spot shapes in RHEED and LEED were simulated by kinematic calculations, which reproduced the experimental results fairly well. It was confirmed that the characteristic spot shapes can be explained by refraction effects and Laue function of diffraction intensity. [DOI: 10.1380/ejssnt.2012.18]

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Graphene is ideally suited to electrochemistry by virtue of its high surface area and impressive electronic properties. Nitrogen incorporation can be used to tailor the properties of graphene. Here we present a simple solvothermal technique to produce a nitrogen-containing foam-like macroporous graphene powder doped with up to 15 wt% nitrogen. This is applied as an effective non-precious, metal-free electrochemical catalyst for oxygen reduction in acid media. [DOI: 10.1380/ejssnt.2012.29]

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In this study, we investigated the biocompatibility of gelatin-coated copper nanoparticles. To estimate their cytotoxicity, the coated copper nanoparticles were exposed to osteoblastic cells. The cell proliferation remained above 80% even when the particles concentration increased. When uncoated copper oxide nanoparticles were exposed to the cells, the proliferation ratio rapidly decreased with the concentration reaching 20% under the same conditions. To determine their biodistribution, the nanoparticles were administered to mice through their tail veins. The particles were subsequently found in some organs using an energy-dispersed X-ray spectrometer and inductively coupled plasma-atomic emission spectroscopy. The polymer-coated nanoparticles were observed in the lung, liver and spleen. They were also detected in the urine at higher concentrations than the copper oxide nanoparticles. Thus, the polymer coating is expected to improve biocompatibility by virtue of the excellent cytocompatibility and acceleration of the excretion process. [DOI: 10.1380/ejssnt.2012.33]

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We investigated the electronic and magnetic states of Fe-phthalocyanine (FePc) molecules adsorbed on Au(111) using density functional theory. Comparing two exchange correlation functionals with and without +U correction, we found that the electronic configuration and magnetic moment of FePc in the gas phase are well reproduced by local density approximation (LDA) + U method. For FePc on Au(111), the residual magnetic moments of the molecule calculated by LDA and LDA+U are different, which originates from the difference in charge transfer described by two methods. We also found that the magnetic moment for the bridge configuration is smaller than that for the ontop configuration reflecting the local symmetry. [DOI: 10.1380/ejssnt.2012.38]

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The composition and electronic structure of a Ni₂P(10-10) surface have been investigated with Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), and photoelectron spectroscopy (PES) utilizing synchrotron radiation. As the Ni₂P(10-10) surface was sputtered by Ar⁺ ion (1 keV, 15 min), the concentration of P atoms in the surface region was reduced. As the surface was annealed at elevated temperatures, the concentration of P atoms was increased due to the segregation from the bulk. The segregation was found to proceed rapidly at 260-330°C. The surface before segregation of P atoms gave a diffused (1× 1) LEED pattern, while the pattern changed to a c(2× 4) pattern when the P atoms were segregated on the surface. The change in the surface electronic structure induced by the segregation of P atoms was investigated by PES. It was found that the spectral intensity of the valence band in the region of 0-2 eV was decreased when the P atoms were segregated to the surface, indicating that the 3d levels of surface Ni atoms were stabilized through the formation of bonds with the 3p levels of the segregated P atoms. [DOI: 10.1380/ejssnt.2012.45]

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We have successfully induced pH wave propagation in microchannel by using a mixed reaction solution containing Na₂S₂O₃, KBrO₃, and NaOH. The use of microchannel with different channel width made clear that the narrower channel enabled faster pH wave propagation. The observed acceleration effect was discussed in terms of proton diffusion confinement in the microchannel, which would lead an increase in apparent proton production rate. Furthermore, we have succeeded in the generation of waves of structural change of molecules immobilized on the microchannel wall by the pH wave propagation, which enables us to design future micro-devices that can work autonomously without external biases. [DOI: 10.1380/ejssnt.2012.50]

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The hexagonal phase MoSi₂ was grown using MoS₂ powder as the source material by the molten salt method. The structural and morphological properties of the resultant silicides are characterized. As a comparison, the structural and compositional characterizations were made for the Mo-silicides grown on a Mo substrate and a Mo-Ti alloy compact. It was revealed that the homogeneity of the chemical composition of the silicides grown using MoS₂ is improved, except for the existence of the Si source powders, though a small amount of S remained in the powder. The layered structure of MoS₂ with a hexagonal crystalline structure would affect the growth morphology and enhance the formation of the hexagonal MoSi₂. A simple growth procedure to fix the crystalline structure using an appropriate starting material under a preferable growth environment is proposed. [DOI: 10.1380/ejssnt.2012.55]

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Contact potential difference (CPD) of Au/TiO₂ model catalysts was measured by Kelvin probe force microscopy (KFM). The CPD of Au particles was lower than that on the TiO₂(110) surface and the difference of CPD between them increased with the particle height. By applying the parallel disk model, the work function difference and the charge density at the Au/TiO₂ interface were estimated to be 0.19 eV and 0.01 C/m², respectively. We have previously measured local barrier height (LBH) of Au/TiO₂ by scanning tunneling microscopy. From the results of CPD and LBH measurements, we found a possibility that the localized charge at the Au/TiO₂ interface plays some role in the catalytic activity of Au catalysts. [DOI: 10.1380/ejssnt.2012.59]

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Molecular modeling techniques were used to investigate the permeability and selectivity of various natural gas components through nano-porous polyimide membranes for the environmentally-friendly “Green” separation of natural gas. The polyimide membranes showed the ability of creating nano-scale channels within the polymeric matrix during the molecular mobility of the polymeric chains through which specific gas molecules can penetrate the membrane surface. The four natural gas components investigated in this study were methane, ethane, propane and butane, all hydrocarbon materials of similar basic chemical structures. The self-diffusion coefficients of the gas molecules were thus used to express the permeability of the various gases through the membranes since the solubility of the gas molecules in the polymeric substances were assumed to be constant. Methane showed a noticeably high self-diffusion coefficient calculated from the application of Einstein relation to the generated molecular dynamics trajectories. All other gases had similar values for the self-diffusion coefficients, which indicate the ability of the methane molecules to penetrate the polymeric membrane in a much larger speed due to a possible matching between the methane molecular size and the size of the interconnected nano-channels within the membranes. The results also showed that the polymer molecules had lower self-diffusion coefficients than the gas ones due to the large size of the polymeric segments. Other structural parameters such as the radial distribution function in direct relationship to the local packing of the polymeric segments and penetrant molecules are also illustrated. [DOI: 10.1380/ejssnt.2012.63]

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Normal incidence X-ray standing wave (NIXSW) method was applied to the determination of geometrical location of atoms in organic molecules on oxide surface. The system investigated was alkyl phosphonic acid (C₁₀) adsorbed on a sapphire surface, which is one of the candidate systems for self-assembled monolayer (SAM) on oxides. The sample surface was irradiated by synchrotron soft X-rays (λ: 0.3∼0.6 nm) from the surface normal, and the intensities of photoelectrons were plotted as a function of the photon energy. As a result, we observed clear modulations of photoelectron intensity around 3050 eV due to the standing wave from the sapphire substrate. Compared with the simulation using the crystal parameters, it was found that the phosphorus atoms are located at 0.11 nm from the surface, while the constant height was not observed for carbon atoms. The results are in consistent with the observations by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) where the molecules form SAM on the sapphire surface through the phosphonic acid, while the alkyl chain is located at the upper side. The present results shed light on the further applications of NIXSW method to the structure analysis of atoms and molecules on insulating materials like oxides. [DOI: 10.1380/ejssnt.2012.69]

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Aromatic polyamide nanofibers with trifluoromethyl (CF₃) groups were fabricated from 4,4'-diphenyldicarbonyl chloride and 2,2'-bis(trifluoromethyl) benzidine in a dioxane solution containing water using a precipitation polymerization method. The morphology of the fibers obtained depended on the water content in the reaction solvent and the monomer concentration. The product prepared in the dioxane solution with a water content of 9 vol% was composed of intimately-interconnected fibers with a diameter of ca. 50 nm, and showed a high affinity for the reaction solvent to form a gel. The product showed excellent thermal stability, in which the thermal decomposition temperature at 5% weight loss was 496°C . Also, it was soluble in sulfuric acid, N-methylpyrrolidone and dimethyl acetoamide but was insoluble in many other solvents, indicating excellent chemical resistance. The products obtained before and after drying showed different swelling behaviors in poor solvents. The specific surface area of the product was found to be affected by the solvent treatment before drying. [DOI: 10.1380/ejssnt.2012.74]

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We established the metal-oxide nanoparticles dispersion technology using Glyceryl-N-(2-methacryloyloxyethyl) urethane (GLYMOU®) with high affinity for the inorganic materials, such as zirconia (ZrO₂, titania (TiO₂, and silica (SiO₂. The high refractive index optical films were prepared by using ZrO₂nanoparticles (grain size: 3 nm) and GLYMOU®. The films were colorless and transparent. As a ZrO₂ concentration increased up to 80 wt%, refractive index showed 1.70 at wavelength of 589 nm. Solid-state NMR and first density functional theory (DFT) study confirmed that GLYMOU® was strongly coordinated to the ZrO₂ surfaces with hydroxyl groups and urethane bond. The dispersion state of nanoparticles in the hybrid films was investigated by combination of grazing incidence small angle X-ray scattering (GISAXS) and transmission electron microscope (TEM). GISAXS measurements and TEM observations, ZrO₂ nanoparticles were finely dispersed in the poly-GLYMOU® matrices. [DOI: 10.1380/ejssnt.2012.85]

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The dicyano(phthalocyaninato)iron molecular conductor shows the Giant Magnetoresistance (GMR) effect. In order to investigate the effect of the molecular structure and charge on the X-ray absorption in the Fe(Pc)(CN)₂ molecule, we measured the Fe K-edge X-ray Absorption Near Edge Structure (XANES) spectra in the TPP[Fe(Pc)L₂]₂ (L=CN, Br, and Cl), DMDP[Fe(Pc)(CN)₂], and [(n-C₇H₁₅)₄N][Fe(Pc)(CN)₂]. In 7134-7152 eV, we found the clear difference in the XANES spectra between these Fe(Pc)(CN)₂ compounds. Our multiple scattering calculations indicate that the local structure of the iron and CN ligand, which tends to be changed by the nominal charge in the Pc ring, causes the spectral change. [DOI: 10.1380/ejssnt.2012.92]

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Magnetic anisotropy of alternately layered FeNi thin films grown on Ni(3--21 ML)/Cu(001) is investigated by means of the X-ray magnetic circular dichroism (XMCD). Perpendicular magnetic anisotropy is observed when the substrate Ni is thicker than 15 and 20 ML for 4 and 6 ML FeNi films, respectively, while in-plane magnetic anisotropy appears at the thinner substrate Ni region. By comparing with the magnetic phase diagram calculated from the magnetic anisotropy energies, which are obtained by the XMCD study [M. Sakamaki and K. Amemiya, Appl. Phys. Express 4, 073002 (2011)], we show that the phase boundary of the present samples shifts so as to prefer the in-plane magnetic anisotropy. This might be caused by the structural relaxation in the substrate Ni. [DOI: 10.1380/ejssnt.2012.97]

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We measured the dynamic friction of nano-sliding between graphite surfaces using a new apparatus. This apparatus enables us to obtain the frictional force of nano-sliding down to a sub-atomic distance. For large sliding distances above 0.68~nm, it was found that the frictional force, i.e., the energy dissipation per distance, is constant. In contrast, for small sliding distances below 0.68~nm, this force was proportional to distance. From these observations, we can conclude that the mechanism of dynamic friction undergoes a drastic change when the sliding distance becomes smaller than the lattice constant. [DOI: 10.1380/ejssnt.2012.100]

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Mn-doped TiO₂ thin films were produced by spin coating on FTO glass substrates to investigate the effects of Mn concentration on the structural, morphological, and optical properties of the films. Titanium isopropoxide and manganese chloride tetrahydrate were used as titanium and manganese sources respectively, in the precursor solution with isopropanol. The solution was added drop-wise on the substrate which was spun at 2000 rpm; annealing was done in air at 500°C for 5 h. Films with very low dopant concentrations (≤ 1 wt%) were composed of anatase; those with moderate concentrations (3—5 wt%) showed the presence of anatase and rutile; while those with high Mn concentrations (≤ 7 wt% Mn) showed rutile formation. Increasing the dopant concentrations resulted in a slight increase in the surface roughness, except for the sample with 15 wt% Mn, that showed surface dimple formation. The films containing ≤ 10 wt% Mn showed similarity in grain sizes (∼ 10 nm) and thickness (∼ 300 nm). All the films showed relatively high transparencies, with the absorption edges shifting to longer wavelengths with increasing Mn levels. The optical indirect band gaps of the films decreased from 3.32 eV to 2.86 eV, and this data suggests that the formation of shallow trapping sites and reduced rate of electron-hole recombination are the result of the variable valence of Mn. [DOI: 10.1380/ejssnt.2012.103]

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The electrical resistivity and the barrier property of Tantalum nitride (TaN) thin films were systematically investigated as a function of annealing temperature using two different types of MIS structures of TaN/SiO₂/Si and Cu/TaN/dielectric/Si(100), where either the thermally grown SiO₂ (th-SiO₂) or spin-on dielectric (SOD) hydrogen silsesquioxane (HSQ) films was used as a dielectric layer. We observed that the resistivity of TaN thin films before Cu deposition became lower with the growth of TaN(200) as compared with the growth of TaN(111) and TaN(220). Cu diffusion barrier properties of MIS diodes with TaN films were improved up to 500°C for both dielectric films due presumably to the decrease in sputter damage of dielectric films by annealing, while those without TaN thin films were degraded due to the diffusion of Cu into the dielectric films. The oxygen desorption from dielectric films and the oxidation of TaN films due to the reverse-sputtering of dielectric films during the sputtering of Ta in N₂ is possible model of sputter damage. [DOI: 10.1380/ejssnt.2012.107]

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To investigate the proton transport properties of the Nafion thin films on MgO(100) substrates, impedance measurements of the 60 and 400 nm thick thin films were carried out. The proton conductivity of two thin films were quite lower values compared to that of the commercial Nafion membrane, and the thickness dependence of the proton conductivity was also observed. To investigate in-plane and out-of-plane molecular vibrations in an identical 400 nm thick film of Nafion on the MgO(100) substrate, an infrared p-polarized multiple-angle incidence resolution spectrometry (p-MAIRS) technique was carried out. The in-plane spectrum showed well-known spectrum, however, the out-of-plane spectrum was quite different compared to the in-plane spectrum. The largely different shapes of the spectra clearly indicate that the 400 nm thick film of Nafion has an anisotropic molecular structure. [DOI: 10.1380/ejssnt.2012.114]

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We have studied the electronic structure within the topmost two quintuple layers (QL) on vacuum-cleaved n- and p-type Bi₂Te₃(111) at 10 K by angle-resolved photoelectron spectroscopy. Tunable synchrotron radiation maximized the surface sensitivity of photoelectrons. The gapless surface-state band (SSB) in the angle-resolved photoelectron spectra clearly demonstrates the topological nature of the samples. Below the SSB, the bulk valence bands (BVB) is observed. Against the three-fold symmetry of the crystal structure, the k_|| dispersion of the BVB is highly symmetrical around the Γ, which indicates the six-fold symmetry. Moreover, most of the BVB show almost flat k_⊥ dispersion perpendicular to the surface. These facts are the experimental evidence of a strong modification of the valence bands within the topmost two QLs into highly two-dimensional states by the advent of the surface. [DOI: 10.1380/ejssnt.2012.117]

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We study experimentally the dependence of fluorescence resonance energy transfer (FRET) efficiency on the distance between donors and acceptors that are embedded in a supported lipid bilayer. The FRET efficiencies are determined by comparing the donor fluorescence intensities before and after acceptor photobleaching. The obtained data are compared with a theory that considers multiple donors and multiple acceptors existing in a two-dimensional field. We achieve good qualitative agreement in terms of the relationship between the FRET efficiency and the donor-to-acceptor distances. The Förster radius is also estimated from the comparison, which shows good quantitative agreement. The significance of the present demonstration is in showing that acceptor photobleaching experiments can quantitatively evaluate the FRET phenomenon, which indicates that the supported lipid bilayer behaves as an ideal two-dimensional fluidic system for embedded molecules. [DOI: 10.1380/ejssnt.2012.121]

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We discuss recoil effects from extended molecular orbitals in simple molecular crystals excited by high-energy X-ray photons. Because of Debye-Waller factors the interference effects between photoelectron waves emanating from different atomic sites can be neglected, and the Gelius formula is safely used, which provides us with simple expression of photoemission bands. This formula can explain the recoil energy shift and energy dependence of the intensity of each level. We apply it to the photoemission bands from acetylene and diacetylene molecular crystals in the energy range from 125 to 1200 eV. Hydrogen recoil shift is much larger than carbon, however it is hard to observe recoil effect due to the hydrogen recoil because of its quite small photoionization cross section even in this intermediate energy region. Additionally, we expect that useful information which is obtained from the energy dependence of these bands: the C 2s and 2p components in each molecular orbital can be estimated roughly from the energy dependence. [DOI: 10.1380/ejssnt.2012.128]

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Nanometer-thick hexagonal boron nitride thin films were grown by thermal chemical vapor deposition on polycrystalline Ni, Co, and Cu substrates. A thicker and more regularly stacked film was grown on a Ni substrate, whereas a smaller film thickness and more turbostratic stacking or smaller domain size were observed on Cu. Intermediate situations were observed on Co. The substrate material dependence strongly suggests that the substrate plays an important role in h-BN growth, like it does in graphene growth, although nitrogen is almost insoluble even in Ni. Grain boundaries may accommodate boron and nitrogen atoms at a growth temperature. [DOI: 10.1380/ejssnt.2012.133]

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Interactions of indium (In) and silicon (Si) atoms have been found to catalyze certain organic chemical reactions with high efficiency. In a recent paper [S. Yoshimura, et al., Appl. Surf. Sci., 257, 192 (2010)], it has been demonstrated that an In injected SiO₂ thin film formed under specific ion beam conditions catalyzes a reaction of benzhydrol with acetylacetone. In this study a technique to implant bismuth (Bi) ions into SiO₂ thin films has been developed with highly controlled ion doses and injection energies for the formation of thin films that promote Bi(III) catalysis in organic chemistry. For this purpose, the Freeman-type ion source of our beam system was modified with a new sputtering target. In addition, sticking probabilities of Bi have been obtained with the use of a quartz crystal microbalance. Although efficiency of catalytic reactions by a Bi implanted SiO₂ thin film is yet to be improved, the technique provides a Bi-Si based novel catalyst of a thin film type. [DOI: 10.1380/ejssnt.2012.139]

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We study the energy- and angular-dependence of bulk and surface plasmon losses in low- and intermediate-energy region (< 1000 eV), and investigate the applicability of the quantum Landau formula which can explain overall plasmon loss features accompanied by core level photoemission. As an example, we calculate the Al 2s photoemission in the photoelectron kinetic energy range from 60 to 1000 eV measured at normal to the surface and at small take-off angles (10° and 30°). For the normal emission the quantum Landau formula gives quite similar results to those without the high-enegy approximation even at 60 eV. On the other hand we observe the considerably large difference at the grazing angle emission (10°). Even at 30° we can safely apply the quantum Landau formula for the plasmon analyses above 250 eV. [DOI: 10.1380/ejssnt.2012.145]

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Electronic structures of a novel interface formed by coverage of organic semiconductor zinc-phthalocyanine (ZnPc) onto a nanometer-thick Ag thin-film with quantized electronic states were investigated by means of angle-resolved photoelectron spectroscopy (ARPES). While the highest occupied molecular orbital position of ZnPc accords with those of a ZnPc overlayer on a bulk Ag substrate having been reported previously, an interface state (IS) revealed different energy position with respect to the bulk case. Absence of the angular-dependence of the IS position strongly suggests that this state is localized at each ZnPc molecule. [DOI: 10.1380/ejssnt.2012.149]

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Spin polarized surface states of Bi(111) film fabricated on Si(111) surface have been investigated by means of high-resolution spin-resolved photoemission spectroscopy. In contrast to the Rashba-type spin-split ideal two-dimensional electron gas in which the spin orientation is locked in-plane and tangential to the electron momentum, significant out-of-plane spin polarization has been observed in the surface states which are forming the hole pocket. The out-of-plane spin polarization is anti-symmetric with respect to Γ-M line and vanishes at the line suggesting that the out-of-plane polarization is derived from the three-fold symmetry of the Bi crystal. The magnitude of the out-of-plane spin components depends on the condition of Bi film fabrication, which is consistent with the recent x-ray diffraction results suggesting the existence of double domains rotating 180° each other on the Bi(111) film grown on Si(111) surface. [DOI: 10.1380/ejssnt.2012.153]

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I have fabricated gold and silver nanoparticle layers on amino-terminated glass substrates by immersion processes from aqueous colloidal solutions of gold and silver nanoparticles. The composition ratio of nanoparticles on the modified substrates was varied by the mixing ratio of corresponding colloidal solutions of nanoparticles. Raman signals of rhodamine 6G were observed on the nanoparticle-modified substrates. In the case of the mixed gold and silver nanoparticle-modified substrates, the intensities of the Raman signals were larger than the intensities expected from a simple proportional sum of the Raman signals obtained using a gold nanoparticle layer or a silver nanoparticle layer. The nonlinear enhancement properties of the Raman signal intensities may be attributable to unique localized surface plasmon resonance between the gold and silver nanoparticles. [DOI: 10.1380/ejssnt.2012.157]

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Amorphous Al₂O₃ films have been deposited on single-crystal ZnO(1-100) substrates by atomic layer deposition at 100°C. Interfacial electronic band structure of Al₂O₃/ZnO heterojunction has been characterized by X-ray photoelectron spectroscopy. Based on binding energies of core-levels and valence band maximum values, valence band offset has been found to be 0.8 ± 0.2 eV for the Al₂O₃/ZnO heterojunction. It shows type-I band configuration with conduction band offset of 2.5 ± 0.2 eV. The effect of surface treatment of ZnO using H₂O₂ on C-V properties of Al/Al₂O₃/ZnO has been investigated. Al/Al₂O₃/ZnO with the H₂O₂ treatment shows better electrical properties than the same structure without the H₂O₂ treatment. [DOI: 10.1380/ejssnt.2012.165]

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The CuO/Cu₂O nanowire axial heterostructures were fabricated by a thermal oxidation technique in air. These nanowire structures resulted from CuO nanowire growth followed by Cu₂O formation. These nanowires were divided into two regions. One is the top half part of the nanowire with CuO domains, and the other part is the bottom half of the wires with Cu₂O domains. The structural property of the CuO/Cu₂O nanowire axial heterostructures was clarified in detail. Both the CuO and the Cu₂O have domain boundaries parallel to the growth direction. The specific relationship of the crystalline orientation between the CuO and Cu₂O shows that CuO [110] or [1 10] is nearly parallel to Cu₂O [110] mostly along the growth directions. The growth condition dependence of the morphological structure was also examined. A simple axial nanowire heterostructure fabrication technique using the compositional modification was developed. [DOI: 10.1380/ejssnt.2012.175]

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The research covers investigation on physical modification of pure cotton fabric using β-CD and its derivative i.e. randomly methylated β-CD (MCD). The obtained material was investigated by means of properties changes when compared to native cotton. The research on retention of small organic molecules and water was done as well. According to obtained results it might be stated that physical modification allow to avoid toxic reagents needed for chemical modification and the material possess interesting retention properties. However the application of obtained fabrics are limited to the single-use application due to washing out of carbohydrate from the cotton matrix. [DOI: 10.1380/ejssnt.2012.180]

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