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Environmental pollution by organic dyes used in industry is a serious problem in developing countries. Environmentally friendly treatment methods are being studied because conventional methods require chemical or additional decomposition treatment. In particular, oxidation via a photocatalyst is a promising alternative due to its chemical and physical stabilities and low cost. However, electron-hole recombination limits the photocatalytic activity in semiconductor photocatalysts such as ZnO and TiO2. This study investigates control of electron-hole recombination of the photocatalyst by loading Au on ZnO (Au/ZnO). Using the Ultrasonic Spray Pyrolysis (USP) method, Au/ZnO particle generation is easily achieved under various conditions. XRD analysis confirms the crystal peaks of ZnO and Au. The EDX mapping and STEM images of the particles show that the Au crystals are well dispersed in the inner and outer portions of ZnO. The photocatalytic decomposition rate of organic dye (Rhodamine-B) is faster than that of ZnO in all Au/ZnO particles, and the best photocatalytic activity occurs in particles with 0.1 mass% Au supported on ZnO particles. In addition, optimal photolysis activity occurs in 100 mL of 5 mg/L RhB aqueous solution and 10 mg dose of Au/ZnO particles. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

If graphene and related 2D materials are to be used commercially, buyers need to have confidence in the measured properties of the material they obtain from suppliers. Scientists from international standards committees describe how the first joint ISO/IEC measurement standard, published this month, will help.

ZnO/Au is expected to exhibit catalytic properties by absorbing ultraviolet and visible light because ZnO and Au nanoparticles can absorb ultraviolet and visible light, respectively. Doping studies on Au nanoparticles on ZnO (ZnO/Au) have been conducted to expand the absorption wavelength range. This study generates ZnO/Au particles by an ultrasonic spray pyrolysis method (USP). To prevent particle aggregation, Triton X-100, a non-ionic surfactant, is added, and its effects are examined. The generated ZnO/Au particles are characterized using different methods. SEM reveals the particle size is several micrometers, while XRD analysis indicates that ZnO and a metallic Au crystalline are present. The TEM images of the particles show that the Au crystals are well dispersed in the inner and outer portions of ZnO. UV-Vis spectroscopy confirms that the smaller the Au particle size, the higher the visible absorption peak near 400 nm. Adding Triton X-100 shifts the absorption peak toward the longer wavelength side but improves the aggregation of Au particles.

This chapter provides an overview of what standards are, why they are important, and how they are developed. There is a focus on the work of standards committees relevant to nanotechnology measurement and characterization with tables detailing the standards that are currently available for a large number of different techniques, materials, and applications at the nanoscale.

金沢大学理工研究域自然システム学系, The slip flow effect is often brought out to explain the reduction in pressure drop for nanofiber filters. Kirsch, Stechkina, and Fuchs (1973) studied the slip flow effect on the pressure drop of fibrous filters consisting of micron fibers, and proposed an empirical equation to predict the dependence of the dimensionless drag, F, on the Knudsen number, Kn, with considering non-uniformity of fiber packing. However, their empirical equation was derived based on the experiments with filters consisting of micron fibers so that the empirical equation is not yet verified for nanofiber filters. In the present work, we used various commercially available nanofiber filters with various physical properties, and the pressure drop was measured at low pressures in order to examine the validity of the empirical equation. As a result, we found that the empirical equation is valid even for nanofiber filters with a large inhomogeneity factor at a large Kn up to 20. © 2017 Elsevier Ltd, Embargo Period 24 months

More than 200,000 tons of scallop shells are disposed annually 1 alone in Japan. Nanoparticles derived from scallop shells have the potential to adsorb gaseous formaldehyde; therefore such discarded shells have now been tested as additive filler in plywood adhesive by mixing high specific surface area, urea-modified shell nanoparticles with a resorcinol?formaldehyde resin; with this procedure it was found that the emission of formaldehyde from the resulting plywood could be substantially reduced. The urea-modified scallop shell nanoparticles were prepared by two different methods: (i) by a dry method in which the shells were treated with planetary ball-grinding under ambient conditions ? a completely dried powder was obtained after addition of the surface-modifying urea solution; (ii) by a moist method by treating dry-ground shell particles in a wet grinding process with the urea solution, followed by the use of centrifugation to obtain a paste. The specific surface area of the nanoparticles obtained by both treatments was 42 ± 3 m213 /g. Measurement of the subsequent formaldehyde emission showed that the addition of the modified scallop shell nanoparticles substantially reduced the formaldehyde emission from plywood; the reduction depends from the specific mass uptake of urea on the nanoparticles which especially was the case when resins containing nanoparticles processed by the moist method were used.

In order to facilitate reliable and efficient determination of both the particle number concentration (PNC) and the size of nanoparticles (NPs) by single-particle ICP-MS (spICP-MS) without the need to correct for the particle transport efficiency (TE, a possible source of bias in the results), a total-consumption sample introduction system consisting of a large-bore, high-performance concentric nebulizer and a small-volume on-axis cylinder chamber was utilized. Such a system potentially permits a particle TE of 100 %, meaning that there is no need to include a particle TE correction when calculating the PNC and the NP size. When the particle TE through the sample introduction system was evaluated by comparing the frequency of sharp transient signals from the NPs in a measured NP standard of precisely known PNC to the particle frequency for a measured NP suspension, the TE for platinum NPs with a nominal diameter of 70 nm was found to be very high (i.e., 93 %), and showed satisfactory repeatability (relative standard deviation of 1.0 % for four consecutive measurements). These results indicated that employing this total consumption system allows the particle TE correction to be ignored when calculating the PNC. When the particle size was determined using a solution-standard-based calibration approach without an NP standard, the particle diameters of platinum and silver NPs with nominal diameters of 30-100 nm were found to agree well with the particle diameters determined by transmission electron microscopy, regardless of whether a correction was performed for the particle TE. Thus, applying the proposed system enables NP size to be accurately evaluated using a solution-standard-based calibration approach without the need to correct for the particle TE.

We investigated the capturing mechanisms of highly charged macromolecular ions of polyethylene glycol electrosprayed onto a metal screen. Our experiments assessed how the charge state, size of the macromolecular ions, and filtration velocity affected the penetration of the ions through the metal screen. The single fiber efficiencies were plotted as functions of the Peclet number and image force parameter. Highly charged molecular ions had much higher collection efficiencies than neutralized macromolecules, suggesting the presence of a strong image force between the ions and metal surface. The single fiber efficiency by image force was proportional to the square root of an image force parameter predicted by theory. When using the prefactor of 9.7 proposed by Alonso et al. (2007), we found fair agreement between the experimental data and theoretical predictions on the collection efficiency of highly charged molecular ions with mobility diameters from 2.6 to 4.8 nm and numbers of electrical charges from 2 to 7. The experimental evidence from our study reveals that image force contributes strongly to the collection of multicharged macromolecular ions by a metal wire screen. © Taiwan Association for Aerosol Research.

Main text A pilot study for the thickness measurement of HfO2 films was performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The aim of this pilot study was to ensure the equivalency in the measurement capability of national metrology institutes for the thickness measurement of HfO2 films. In this pilot study, the thicknesses of six HfO2 films with nominal thickness from 1 nm to 4 nm were measured by X-ray Photoelectron Spectroscopy (XPS), X-ray Reflectometry(XRR), X-ray Fluorescence Analysis (XRF), Transmission Electron Spectroscopy (TEM), Spectroscopic Ellipsometry (SE) and Rutherford Backscattering Spectrometry (RBS). The reference thicknesses were determined by mutual calibration of a zero-offset method (Medium Energy Ion Scattering Spectroscopy (MEIS) of KRISS) and a method traceable to the length unit (the average thicknesses of three XRR data except the thinnest film). These reference thicknesses are traceable to the length unit because they are based on the traceability of XRR. For the thickness measurement by XPS, the effective attenuation length of Hf 4f electrons was determined. In the cases of XRR and TEM, the offset values were determined from a linear fitting between the reference thicknesses and the individual data by XRR and TEM. The amount of substance of HfO2, expressed as thickness of HfO2 films (in both linear and areal density units), was found to be a good subject for a CCQM key comparison. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCQM.

Coagulation coefficient of aerosol particles due to Brownian motion is an important issue to describe change in particle size distribution. Motion of aerosol particles is diffusive in continuous region (small Knudsen number; Kn), or like free molecular motion of gaseous molecular in free molecular region (large Kn). Fuchs (1964) presented an expression of coagulation coefficient in transition regime by a so-called “Flux Matching” method. In his method, transportation of particles inside of the “limiting sphere” is assumed to be like free molecular, or diffusive outside of the sphere. These days, some researchers presented coagulation coefficient of aerosol particles by direct calculation of motion of aerosol particles. They employed Langevin dynamics equation to represent the stochastic motion of aerosol particles. In this study, we developed new model to calculate the coagulation coefficient. Our model employed spherical calculation space in which one scavenging particle is in the center of it: the calculation sphere moves together with the motion of the scavenging particle. The coagulation coefficient can be calculated from the mean time between collisions and the concentration of collision particles. By using the above numerical model, we have calculated the coagulation coefficient of spherical particles of from 4 nm to 100 nm in diameter.

Results of proficiency testing (PT) undertaken to assess the analytical skills in Japanese laboratories are presented. The PT was coordinated jointly by the National Metrology Institute of Japan (NMIJ) and the National Food Research Institute (NFRI), in which the determination of As, Cd, Fe, Mn and Zn in a dried powdered squid powder was carried out in compliance with the international standard ISO/IEC 17043:2010. A prescribed protocol for the determination of the moisture content of the sample was given to the participants beforehand. Any sample preparation/extraction methods were not prescribed, and a variety of methods was thus applied by the 118 participants. Reported results were assessed using the En-number and z-score approaches in accordance with ISO/IEC 17043 and the international harmonized protocol for PT. Results of this PT are reviewed in detail, and technical problems leading to some unsatisfactory results are discussed.

We report a simple strategy to synthesize vaterite/calcite mesoporous calcium carbonate through collisions and organization of colloidal particles accelerated by mechanical stirring. Mechanically stirring the precursor colloidal dispersion can control the calcium carbonate polymorphs.

There has been only limited information about the vertical chemical structure of the atmosphere, so far. We conducted aerial observations on 11, 12, and 14 December 2010 over the northern part of the East China Sea to analyze the spatial distribution of atmospheric pollutants from East Asia and to elucidate transformation processes of air pollutants during the long-range transport. On 11 December, a day on which Asian dust created hazy conditions, the average PM10 concentration was 40.69 μg m−3, and we observed high concentrations of chemical components such as Ca2+, NO3–, SO42−, Al, Ca, Fe, and Zn. The height of the boundary layer was about 1200 m, and most species of pollutants (except for dust particles and SO2) had accumulated within the boundary layer. In contrast, concentrations of pollutants were low in the boundary layer (up to 1000 m) on 12 December because clean Pacific air from the southeast had diluted the haze. However, we observed natural chemical components (Na+, Cl–, Al, Ca, and Fe) at 3000 m, the indication being that dust particles, including halite, were present in the lower free troposphere. On 14 December, peak concentrations of SO2 and black carbon were measured within the boundary layer (up to 700 m) and at 2300 m. The concentrations of anthropogenic chemical components such as NO3–, NH4+, and Zn were highest at 500 m, and concentrations of both anthropogenic and natural chemical components (SO42−, Pb, Ca2+, Ca, Al, and Fe) were highest at 2000 m. Thus, it was clearly indicated that the air above the East China Sea had a well-defined, layered structure below 3000 m.

Aerial observations of atmospheric pollutants were made over the East China Sea to analyze the transport of air pollutants, especially nitrogen oxides, from East Asia. Three flights each were conducted in October 2009 (autumn) and December 2010 (winter). Onboard measurements of gaseous total odd nitrogen species, gaseous nitric acid (HNO3(g)), O3, SO2, CO and black carbon were made and particles were collected on filters for ionic and metal component analyses. The NO3−(p)/T.NO3 (T.NO3 = HNO3(g) + NO3−(p); NO3−(p) indicates particulate nitrate) ratios were less than 0.5 in most cases. Exceptions were 17 October and 11 December, when high concentrations of dust particles (Kosa) were transported. The average T.NO3/NOy (NOy indicates total odd nitrogen species) ratio in winter was 0.59, and that in autumn was 0.71. In addition, positive and negative correlations between NOy − T.NO3 and ozone were observed in autumn and winter, respectively. These results indicate that the main components of NOy − T.NO3 are NOx and its descendant photochemical products, such as peroxyacyl nitrates and alkyl nitrates, in winter and autumn, respectively. Ratios of Na+ to Cl− + NO3− in particles were close to the seawater ratio for observations in both autumn and winter, save for the Kosa events. The main NO3−(p) formation process was the reaction of HNO3(g) with sea salt aerosols during autumn and winter. On the other hand, NO3−(p) was generated by the reaction of HNO3(g) with dust particles and sea salt during the Kosa events. The fraction of NH4NO3 in NO3−(p) was very small.

Scallop shells are disposed more than 200,000 ton per year in Hokkaido. Here we report effective uses for discarded shells as an additive of plywood adhesive because some plywood adhesives emit formaldehyde that leads to limit on its use. We produced adhesive resin filling ground shell particles with a high specific surface area to reduce formaldehyde emission from plywood. Nano-sized scallop shell particles were prepared by planetary ball milling under dry condition and subsequent water addition. The emission amount of gaseous formaldehyde from plywood was then estimated. We found that the prepared adhesive including scallop shell nanoparticles exhibited an excellent inhibiting effect on the formaldehyde emission rather than the feed shell.

Nanoparticles with size in the range from 10 nm to 300 nm and from three different materials (Au 10 nm, Ag 20 nm, and PSL 30 nm, 100 nm and 300 nm) were used in this supplementary comparison. The selected nanoparticles meet the requirements of different measurement methods such as Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), and Differential Mobility Analyzer (DMA), Small Angle X-Ray Scattering and for forth. All 37 participating laboratories returned results, but not all laboratories were able to perform measurement of all 5 nanoparticles. In order to determine the degree of equivalence (DOE), two reference values were considered in this comparison: the method dependent reference value (MRV) and the global reference value (GRV). The MRVs were determined for different measurement methods according to the corresponding reported uncertainties and measurement values from the participants. Each measurement method owns its own MRV. Since the measurement data from DLS were very different from and inconsistent with the measurement data from the other methods, the MRV for DLS was used in the En number calculation for the measurement data reported from the DLS method. The GRV was determined from the MRVs and their uncertainties of all the measurement methods except DLS, and was applied in the En number calculations for the measurement data reported from AFM, EM, DMA and SAXS methods. The assumption that the particles are spherical was commonly made in the nanoparticle measurements. Non-sphericity of particles, if exists, could have different impacts on different measurement methods. It is also important to note that the methods used are measuring mean diameters of a population of particles, not just a single particle, and that the meaning of the mean diameter could differ for different methods. Probably if participants include a different specific contribution in the uncertainty in a harmonized way, taking the non-cancelled method-dependent "systematic" errors into account, it may be easier to compare the results. KEY WORDS FOR SEARCH Nanoparticles; Atomic Force Microscopy (AFM); Transmission Electron Microscopy (TEM); Scanning Electron Microscopy (SEM); Dynamic Light Scattering (DLS); and Differential Mobility Analyzer (DMA); Small Angle X-Ray Scattering Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Time-resolved data for size distribution, number concentration and chemical composition of atmospheric aerosols were taken from March 9 to 16, 2012 during Fukue Site Atmospheric Aerosol Observation Campaign (128.7°E, 32.8°N) organized by ASEPH (Impacts of Aerosols in East Asia on Plants and Human Health) project. A scanning mobility particle sizer was employed to continuously measure the particle size distribution from 14 nm to 670 nm and the total number concentration of particles (>3 nm) was measured by a condensation particle counter. Very large amount of polluted air mass transportation (PM2.5 > 65 μg m−3) was observed on March 11, associated with a sudden increase in particle number concentration having a mobility diameter from 100 to 300 nm. The transported air mass contained anthropogenic pollutants such as sulfate (>20 μg m−3), nitrate (>15 μg m−3) and black carbon (>3 μg m−3). Typical new particle formation and growth events were also observed on March 12–13. The onset of particle formation and nucleation bursts was identified at around noon and it is considered that these were nucleated species near the island area. It was found that some new particle formation events were associated with the long range transportation of polluted air mass from East Asian region.

Herein we report colloidal dispersibility of concentrated suspensions containing fatty acid-capped iron nanoparticles and its influence on the static and dynamic magnetorheological (MR) response. The amount of fatty acid absorbed on the surface controls the non-field dispersion state as well as weakly and strongly flocculated structure of the nanoparticles. Both yield stress at B = 0.5 T of an applied magnetic field is ca. 14–16 kPa Because the flocculated structure has a negligible effect on the field-dependence yield stress, the non-field dispersion state mainly determines the turn-up ratio; the ratio of the yield stress at B = 0.5 T to shear stress (at 1 s −1 ) at B = 0. The dynamic measurements indicate that the two dispersion states are different in the field-induced aggregation structures. A viscoelastic linear region appears for a weakly flocculated suspension, and does not for a strongly flocculated suspension. Additionally, the colloidal stability for the two dispersion states is discussed in terms of pair potential energy.

We formed nano-dots using a helium ion microscope (HIM) equipped with a gas injection system. Because of position controllability, the nano-dot markers could be placed efficiently on a specimen using the HIM. The sizes of the dots were controlled by changing the beam radiation time. We tried for the first time to form dots on a rod-shaped specimen to use them as markers for aligning a transmission electron microscope tomographic tilt series before reconstructing 3D images.

Herein we propose a production scheme for conductive films composed of thin graphite sheets with high crystallinity and polymeric resin. The crystalline graphite sheets were successfully produced from natural graphite powder by solution-phase synthesis of graphite intercalation compounds (GICs), following a wet planetary-ball milling under mild conditions. The shear forces in the milling pot lead to a peeling of graphite flakes. Taking into consideration the interlayer bonding force, the delamination should be preferentially done from the expanded GICs interlayer rather than intrinsic graphite one. Some composite films derived from the phenolic resin and flaky graphite sheets displayed much higher electrical conductivities compared to the film from the feed graphite particles. We also demonstrate the stage structure of synthetic GICs affected the film conductivity. The composite films made from exfoliated products of ground (around stage IV) GICs exhibited high electrical conductivity with a small amount of the graphite sheets.

In order to evaluate the potential of surface-discharge microplasma devices (SMDs) as ion sources for high-efficiency electrical charging of nanoparticles, a long SMD was installed in a surface-discharge microplasma aerosol charger (SMAC), and the charging performance of the SMD for aerosol nanoparticles was measured. The intrinsic charging efficiency for 5-nm-diameter particles was approximately 60%, and that for 10-nm-diameter particles was 90% at an aerosol flow rate of 1.5 L · min−1 because a long SMD is capable of generating a uniform concentration of ions over a wide area. The size-dependent charging efficiencies for these aerosol nanoparticles with diameters ranging between 3 nm and 30 nm were in good agreement with those predicted using the diffusion charging theory. The product of ion concentration (N) and charging time (t), estimated via the diffusion charging theory, was 3.0×1013 s · m−3, which is one order of magnitude higher than that for previously reported chargers. These results confirm the high potential of SMDs as ion sources for charging aerosol nanoparticles.

An international interlaboratory comparison of the measurement capabilities of four National Metrology Institutes (NMIs) and one Designated Institute (DI) in the determination of the chemical composition of thin Fe-Ni alloy films was conducted via a key comparison (K-67) of the Surface Analysis Working Group of the Consultative Committee for Amount of Substance. This comparison was made using XPS (four laboratories) and AES (one laboratory) measurements. The uncertainty budget of the measured chemical composition of a thin alloy film was dominated by the uncertainty of the certified composition of a reference specimen which had been determined by inductively coupled plasma mass spectrometry using the isotope dilution method. Pilot study P-98 showed that the quantification using relative sensitivity factors (RSFs) of Fe and Ni derived from an alloy reference sample results in much more accurate result in comparison to an approach using RSFs derived from pure Fe and Ni films. The individual expanded uncertainties of the participants in the K-67 comparison were found to be between 2.88 and 3.40 atomic %. The uncertainty of the key comparison reference value (KCRV) calculated from individual standard deviations and a coverage factor (k) of 2 was 1.23 atomic %. Copyright © 2011 John Wiley & Sons, Ltd.

In this study, we present a new method for placing markers for alignment of tomographic tilt-series of rod-shaped specimen before 3D reconstructions. By this method, markers (gold nanoparticles) were placed only on the carbon layer (referred to as the “marker area”) deposited for protecting the specimen surface against ion beam irradiation; this placement was achieved by vacuum evaporation of gold with the help of a mask fabricated adjacent to the specimen. Experimental results showed that the use of the proposed method facilitates the identification of the markers in the alignment process, because the image of the marker area consists of simple high-contrast images of the gold nanoparticles on the carbon layer. The performance of the proposed method was successfully verified experimentally by applying it to a high-density Au/SiO2 nanocomposite material as a test specimen.

An automatic coarse-alignment method for a tilt series of rod-shaped specimen collected with a full angular range (from alpha=-90 degrees to +90 degrees, alpha is the tilt angle of the specimen) is presented; this method is based on a cross-correlation method and uses the outline of the specimen shape. Both the rotational angle of the tilt axis and translational value of each image can be detected in the images without the use of markers. This method is performed on the basis of the assumption that the images taken at alpha=-90 degrees and alpha=+90 degrees are symmetric about the tilt axis. In this study, a carbon rod on which gold particles have been deposited is used as a test specimen for the demonstration. This method can be used as an automatic coarse-alignment method prior to the application of a highly accurate alignment method because the alignment procedure can be performed automatically except for the initial setup of some parameters.

An orthogonal acceleration Time-of-Flight Secondary Ion Mass Spectrometer (TOF-SIMS) system has been developed with a metal-cluster-complex ion source. The ion source can produce ion beams of massive molecules called metal-cluster-complexes such as Ir 4 (CO) 12 , which has a molecular weight higher than 1000 u. Using the system, TOF-SIMS of a contaminated silicon substrate and a room temperature molten salt (i.e. an ionic liquid) was performed. The ionic liquid N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide, which has a molecular weight of 426 u, consists of a polyatomic cation, [C 8 H 20 ON] + , and a polyatomic anion, [C 2 F 6 NO 4 S 2 ] - . During SIMS analysis, an analytical sample was bombarded with a continuous primary ion beam of either Ir 4 (CO) 7 + or Ar + in a beam energy of 10 keV at an incident angle of 45°. It was confirmed that the use of Ir 4 (CO) 7 + ions enhanced secondary ion intensity compared with that of Ar + ions. Also, experimental results showed that the bombardment of Ir 4 (CO) 7 + caused less fragmentation. In the case of the ionic liquid, cation-attached ionic-liquid molecules were observed in addition to the cation of the ionic liquid.

This paper describes a method for automatic acquisition of a high-resolution transmission electron microscope (TEM) tilt series over the full angular range from −90° to +90° for TEM tomography. The goniometer controller of a conventional TEM was modified to allow external computer control over specimen position along the three translational and one rotational axis. The TEM parameters, stage motion, and image acquisition were synchronously controlled by home-coded software. The shift in the specimen position with each step of rotation was determined at low magnification by the cross-correlation function and then compensated by moving the stage. The image shift coil and objective lens were only used for fine-tuning. As a result, a tilt series over a full angular range was automatically collected at a magnification of around ×200k. The specimen position remained within less than around ±100 nm in the three directions during image collection. [DOI: 10.1380/ejssnt.2010.178]

Composite films composed of graphite particles and polymer resin should exhibit functional properties such as electrical conductivity and elasticity. This study aims to produce fine flaky graphite particles for use as electrical conductive source materials within graphite / phenol resin composite films. We prepared graphite intercalation compounds with exfoliated graphite layers due to the insertion of two types of guest molecules. Then planetary ball wet milling was performed to produce flaky graphite particles by removing the exfoliated layers of the graphite intercalation compounds. Some composite films derived from the phenol resin and the obtained flaky graphite particles displayed much higher electrical conductivities compared to films composed of feed graphite particles. Additionally, we successfully applied the grinding method proposed in this study to decrease the weight fraction of the graphite particles in the composite films, and these films exhibited high electrical conductivities.

To develop a solution-type ion beam source utilizing a wide variety of metal cluster complexes that are stable only in organic solvents, we have investigated an electrospray method for transferring ions from solutions to gas phase. As initial experiments, we have studied electrospray characteristics of ethanol solutions containing a room-temperature molten salt (i.e., an ionic liquid) and acetic acid as alternatives to solutions of metal cluster complexes. In electrospray experiments, we used a stainless-steel capillary with an inner diameter of 30 μm. Experimental results showed that electrosprayed currents increased with applied voltage in both positive-ion and negative-ion modes. In addition to positive currents, stable negative currents were also confirmed to be produced. Current exceeding 250 nA was produced at 2 kV with a flow rate of 2 μL/min at a concentration of 1 × 10−3 mol/L. It was confirmed that several nA out of electrosprayed currents were delivered through an orifice (120 μm internal diameter) into a vacuum chamber. Experimental results indicate that the electrospray method seems to be applicable to an ion beam source for utilizing massive metal cluster complexes in solutions.

A new ion source using massive molecules called metal cluster complexes has been developed. Metal cluster complexes are chemically-synthesized organometallic compounds, which have a wide range of chemical compositions with high molecular weight. The ion source is compact enough to be installed in commonly used secondary ion mass spectrometry (SIMS) systems. Using the ion source, sputtering characteristics of silicon bombarded with normally incident Ir4(CO)7+ ions were investigated. Experimental results showed that the sputtering yield at 10 keV was 36, which is higher than that with Ar+ ions by a factor of 24. In addition, SIMS analyses of boron-delta-doped silicon samples and organic films of poly(methyl methacrylate) (PMMA) were performed. Compared with conventional O2+ ion beams, Ir4(CO)7+ ion beams improved depth resolution by a factor of 2.5 at the same irradiation conditions; the highest depth resolution of 0.9 nm was obtained at 5 keV, 45° with oxygen flooding of 1.3×10-4 Pa. Furthermore, experimental results confirmed that Ir4(CO)7+ ion beams significantly enhanced secondary ion intensity in high-mass region.

HfSiON thin films with different thicknesses were prepared by the oxidation of sputter-deposited hafnium nitride (HfN) thin films. Thereafter, the chemical structures were investigated using XPS before and after a rapid thermal anneal (RTA) at a high temperature of 1000 °C. The thinner film of HfN was fully oxidized and HfSiON was formed after oxidation; Si atoms of HfSiON were obtained as a result of out-diffusion from the substrate. However, a majority of HfN bonds in the thicker sample remained unoxidized after oxidation, and subsequent annealing at 1000 °C revealed bond breaking of HfN, N loss, and bond formation of HfO. This suggested that the incorporation of O into the film was the main channel for N loss during high-temperature annealing. The high-resolution cross-sectional transmission electron microscopy (CS-TEM) results indicated that the thinner film was amorphous and the thicker one, crystalline. The existence of HfSiON at the interface in the thinner sample before RTA was considered to suppress the crystallization. Copyright © 2008 John Wiley & Sons, Ltd.

Metal cluster complexes are chemically synthesized organometallic compounds, which have a wide range of chemical compositions with high molecular weight. Using a metal cluster complex ion source, sputtering characteristics of silicon bombarded with normally incident Ir4(CO)7+ ions were investigated. Experimental results showed that the sputtering yield at 10 keV was 36, which is higher than that with Ar+ ions by a factor of 24. In addition, secondary ion mass spectrometry (SIMS) of boron-delta-doped silicon samples and organic films of poly(methyl methacrylate) (PMMA) was performed. Compared with conventional O2+ ion beams, Ir4(CO)7+ ion beams improved depth resolution by a factor of 2.5 at the same irradiation conditions; the highest depth resolution of 0.9 nm was obtained at 5 keV, 45° with oxygen flooding of 1.3 × 10−4 Pa. Furthermore, it was confirmed that Ir4(CO)7+ ion beams significantly enhanced secondary ion intensity in high-mass region.

The surface topography of Si(100) bombarded with 2.5–10 keV Ir4(CO)7+ at an incident angle of 45° was investigated by atomic force microscopy. Experimental results showed that self-organized ripple structures with a wavelength below 30 nm were produced at a beam energy of 5 keV. It was found that the wavelength of the ripples increased with decreasing beam energy, which is different from results obtained using conventional ion beams. In addition, surface roughness proved to increase with decreasing beam energy. The phenomena were explained by considering a substantial decrease in sputtering yield and the subsequent compositional change in the target at lower-beam-energy Ir4(CO)7+ bombardment. Furthermore, the surface roughness was also confirmed to increase with increasing oxygen partial pressure.