To assure the repeatability of the gate etching process, in situ plasma cleaning is used to remove the depositions on the chamber wall. We studied the mechanism of deposition and cleaning of silicon containing films on the chamber wall formed during silicon etching using the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). During the silicon etching with a Cl₂/O₂ plasma, a silicon-oxychloride film grows on the chamber wall due to the oxidation of the etch products. In the growth of the deposition films, the oxygen gas plays a key role. In a pure Cl₂ plasma the deposition is removed even while the silicon etching is proceeding on the wafer. It was also found that the deposition rate is square proportional to the O₂ gas flow rate. A simple kinetic model that attributes the square dependence to the consecutive oxidations of the two adjacent dangling bonds of a silicon atom has been described. Then the in situ cleaning of silicon-oxychloride with SF₆ plasma was investigated with regard to the cleaning rate. Although oxygen gas is often added to the cleaning gas so as to remove commonly seen residues such as carbon or sulfur, there is a concern that oxidation may reduce the cleaning rate. It was confirmed that an oxygen addition of 30 sccm to the SF₆ gas of 150 sccm causes insignificant effect. Further study to increase the cleaning rate revealed that lower pressure and larger total gas flow rate are effective. The effect of pressure is understood combined with the change in the plasma density. On the other hand, the total gas flow rate changes the density of etch products near the chamber wall. It was confirmed that the total gas flow rate does not change the etching rate of silicon-oxychloride on the wafer as it lies near the stagnation point of the gas flow. [DOI: 10.1380/ejssnt.2013.1]

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We present the possibility of o-xylene as a carbon supplier for the synthesis of carbon nanotubes (CNTs) by the liquid-phase pulsed arc method using copper electrodes. Moreover, we investigate the effect of inrush current on the composition of the synthesized material. As inductance from an air-core coil increased, the weight ratio of copper particles tended to decrease dramatically. Moreover, with increasing inductance, the weight of the CNTs tended to increase. These results imply that control of discharge current is important for the synthesis of CNTs by the liquid-phase method. [DOI: 10.1380/ejssnt.2013.8]

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We developed a multi-probe atomic force microscopy (MP-AFM) system using piezo-resistive cantilevers. The use of piezo-resistive self-sensing cantilevers with deflection sensors as probes markedly reduced complexity in the ordinary AFM setup. Simultaneous observation images can be acquired by the MP-AFM under frequency modulation (FM) detection operations. The minimum distance between these probes was 6.9 μm using the piezo-resistive cantilevers fabricated by a focused ion beam. Furthermore, we found that the nanoscale interaction between the probes was detected by determining the change in the amplitude of each cantilever. It was clarified that the interaction effect depended on the vibration amplitude of the cantilever-probe. [DOI: 10.1380/ejssnt.2013.13]

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Non-invasive detachment of Vorticella from a substrate is essential for fabricating a microsystem based on Vorticella. Here, we dry sodium alginate solution and obtain sodium alginate films with fewer uncrosslinked sol regions. Calcium ions cross-link the alginate polymers of the membrane and form a calcium alginate gel. We first culture V. convallaria on the gel membrane. By dissolving the membrane with a chelating agent, we detatch cells non-invasively from the substrate and obtain cells with intact stalks, which can then be placed in a microsystem without waiting for the stalks to grow. The cells can be patterned by lift-off of the calcium alginate membrane. The proposed method provides new processing capabilities and allows for the design and fabrication of a system based on an actuator of Vorticella. [DOI: 10.1380/ejssnt.2013.25]

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Combined effects of electric field and magnetic field on exciton binding energy as a function of dot radius in a cylindrical GaAs_0.9P_0.1/GaAs_0.6P_0.4 strained quantum dot is investigated. The strain contribution includes the strong built-in electric field induced by the spontaneous and piezoelectric polarizations. Numerical calculations are performed using variational procedure within the single band effective mass approximation. The interband emission energy as functions of geometrical confinement, electric and magnetic field strengths in the quantum dot is discussed. The diamagnetic shift of exciton as a function of dot radius is found. The quantum confined Stark shifts of exciton for various dot radii are discussed. Optical rectification in the GaAs_0.9P_0.1/GaAs_0.6P_0.4 strained quantum dot is computed in the presence of electric and magnetic field strengths. Our results show that the optical rectification strongly depends on the spatial confinement, electric field and magnetic field strength. [DOI: 10.1380/ejssnt.2013.29]

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The superhydrophilization of a silicon (Si) surface by atmospheric-pressure plasma jet irradiation was analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS). The Si surface was irradiated with an atmospheric-pressure argon (Ar) plasma jet in air for 5 s. The contact angle of a water drop on the Si surface decreased from 77 to 7° as a result of plasma jet irradiation, meaning that the Si surface became superhydrophilic. TOF-SIMS analysis indicated that the superhydrophilization was due to the removal of hydrophobic polydimethyl siloxane (PDMS) adsorbed on the Si surface and the increase in the amount of the hydrophilic silanol (SiOH) group. Emission spectral analysis of the plasma jet indicated that the SiOH group was formed when hydroxyl (OH) radicals, generated by collisions between high-energy electrons in the plasma and water molecules in air, bond to Si atoms on the surface. [DOI: 10.1380/ejssnt.2013.36]

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In the present study, calcined gibbsite (GB) was prepared by calcination treatment between 200 and 1000°C (GB200-GB1000). The properties of GBs (i.e., the amount of hydroxyl groups, specific surface area, mean pore diameter, and pore volume) were evaluated. GB400 had the highest amount of hydroxyl groups (0.46 mmol/g), as well as the highest specific surface area (295.3 m²/g) and micropore volume (0.036 mL/g). It also provided the highest amount of the adsorbed Pt(IV) and Pd(II), which suggests that the adsorption of Pt(IV) and Pd(II) onto GB is related to the amount of hydroxyl groups, specific surface area, and micropore volume. The optimal pH values for the adsorption of Pt(IV) and Pd(II) onto GB400 were 4.5-5.0 and about 6.0, respectively. The equilibrium adsorption of both cations onto GB400 was reached within 30 min. Moreover, the experimental data of the adsorption of Pt(IV) and Pd(II) onto GB400 was fitted by pseudo-second-order model (r = 0.997-0.999) and the Langmuir equation (r = 0.934-0.953). The calculated thermodynamic parameters ΔG, ΔH, and, ΔS indicate that the adsorption of Pt(IV) onto GB400 is feasible, spontaneous, and exothermic. In addition, the amount of Pt(IV) and Pd(II) adsorbed onto GB400 decreased with increasing chloride ion concentration. [DOI: 10.1380/ejssnt.2013.40]

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Discharge instability at patterned conductive layers on insulating substrates during pulsed-plasma chemical vapor deposition under near atmospheric pressures was studied by observing the distribution of plasma damage spots in the grown film. Instability of the discharge is found to be enhanced at conductive layers, and the density and the size of the plasma damage spots vary with the shape and the size of the conductive pattern. Based on these observations, we propose a simple model, uniformly diluted charge (UDC) model, to explain the damage distribution within the conductive pattern. [DOI: 10.1380/ejssnt.2013.47]

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In this study, the mechanical and tribological properties of polyaniline (PANI) brush are investigated for ultrahigh density data storage system based on atomic force microscope (AFM). A 30-nm-thick PANI brush film is formed on an Au surface by the intermediary of a self-assembled monolayer. The average Young's modulus of the brush is successfully evaluated to be 3.8 GPa by force-deformation curve measurement. And main cause of the friction force between conductive Pt/Ir-coated tip and the brush in the tip scanning is found to be not adhesion force but the roughness by lateral force microscopy. Moreover, it is demonstrated that the PANI brush has better wear resistivity compared with a spin-deposited PMMA film as the recording medium. The good wear resistivity is attributed to the configuration of the polymer brush without physically-absorbed polymer chains. [DOI: 10.1380/ejssnt.2013.53]

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The Casimir interaction between a torsion balance and flat plate is considered using proximity force approximation (PFA) and geometric optics approximation (GOA). Both approximations predict that the parallel configuration becomes unstable as the distance between a torsion balance and flat plate decreases. However, the dependence of the tilt angle at the stable position on the separation is significantly different. The tilt angle obtained by PFA continuously changes over the entire range; however, the discontinuous transition is predicted in GOA. [DOI: 10.1380/ejssnt.2013.60]

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Dissociative adsorption processes of O₂ molecule on Pt(111) surface are explored using quantum dynamical calculations based on coupled-channel method. The explored adsorption sites are the direct dissociative adsorption channels, where the precursor state for O₂ sticking are absent, with certain amount of activation barrier. We find that the dissociative sticking probability of O₂ depicts the sigmoidal (S-shaped) curve in all cases which is a manifestation of the tunneling effect. Moreover, the sticking curve is sensitively dependent on the shape of the activation barrier which affects the width of the transition region. Molecular vibration facilitates sticking and affects the width of the barrier. [DOI: 10.1380/ejssnt.2013.72]

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A near-field optical spectroscopy technique has been developed that collects the nonlinear sum-frequency signal from the surface adsorbed monolayer sample. The sum-frequency signal generated at the surface was collected with a silver-coated multi-mode fiber probe. The metal coating of the fiber effectively eliminates the far-field stray light that enters the core fiber from the outer edge, passing through the clad region. As the tip was pulled away from the sample surface, the sum-frequency signal from the GaAs crystal sample decreased rapidly with increasing tip-sample distance, indicating that the signal is essentially due to the near-field generated by the sum-frequency process. By using the metal-coated multi-mode fiber probe, information about the vibrational structure of the adsorbed molecules at the surfaces is studied. [DOI: 10.1380/ejssnt.2013.76]

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This paper describes curious behaviors in noncontact atomic force microscopy (NC-AFM) line-profiles simulated by the density-functional based tight-binding (DFTB) method. Although NC-AFM observes the surface corrugations in general, these line-profiles show atom-like peaks at vacancy sites. This is caused by a stronger interaction incident to the dangling bond. [DOI: 10.1380/ejssnt.2013.80]

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Molecular orientations of L-serine on Cu(001) as a function of exposure were studied using RAIRS. In the results, the intensity variations of δ(C^∗H) and ν(C^∗H) bands (C^∗ denotes a chiral carbon) caused with increasing the coverage in addition to some common bands with adsorbed alanine on Cu(001). Furthermore, a C-O stretching band in hydroxy group caused blue shift from 1112 to 1141 cm^-1. The bands correspond to weak hydrogen bonding and tight one, respectively. These characteristic spectra are very reasonable to proposed models in the previous study. [DOI: 10.1380/ejssnt.2013.85]

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In the present study, we developed modified activated carbon (KL) for the adsorption of Pb (II). Chemically modified activated carbons (KL-A and KL-B) were prepared by nitric acid and ethylenediamine treatments, respectively. The properties (specific surface area, pore volume, mean pore diameter, acidic or basic functional groups, and pH) of KL, KL-A, and KL-B were investigated by various methods. Contact time, adsorption isotherms, and recovery of Pb (II) were evaluated. Equilibrium adsorption on KL and KL-B or KL-A was reached in about 12 h and 5 h, respectively. The experimental data was fitted to pseudo-second order model and compared with the pseudo-first order model. The optimal pH conditions for the adsorption of Pb (II) was pH = 5.1-5.5. These data were fitted to Freundlich and Langmuir models. Moreover, the adsorption mechanism of Pb (II) on KL-A was related to the ion exchange with acidic functional groups. It would be possible to recover Pb (II) by using nitric acid. The results suggest that KL-A would be useful in the adsorption of Pb (II). [DOI: 10.1380/ejssnt.2013.93]

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Ion beam induced dewetting of thin metallic films has emerged as a promising way to grow metallic nanoparticles in a controlled manner. Metal films tend to dewet from non-reactive substrates upon heating, forming islands, due to the high energies of metal surfaces and interfaces. Ion beam irradiation triggers the self organized formation of nanostructures, and allows control over nanoparticle size distributions, since dewetting is initiated by highly localized (in space and time) thermal spikes along the ion track. From 25 nm cobalt films grown by e-beam evaporation, followed by irradiation with 100 keV Ar⁺ ions, a high density array of nanostructures is formed. AFM scans show their morphological evolution as a function of ion fluence; optimum fluences for narrow particles size distribution have been identified. Glancing angle XRD and Rutherford Backscattering Spectroscopy show evidence of increased substrate exposure as dewetting proceeds. RBS indicates that within the optimal fluence range for nanostructure formation, sputtering and ion beam mixing are not the significant effects in this system. We present ion beam induced dewetting as a well controlled method of forming nanostructured catalysts from metal films. [DOI: 10.1380/ejssnt.2013.99]

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A single-walled carbon nanotube (SWNT) with well-defined structure has a potential as a probe of scanning microscopy. However, SWNT tip has not been applied to practical use yet because of the difficulty in the tip preparation. We have developed a technology for fabrication of SWNT tips with the yield rate of 25%. Various lengths and shapes of SWNT tips were examined as the probe of ultrahigh vacuum scanning tunneling microscopy (STM). We found that the length of SWNT was a crucial factor for the application to STM. Atomic-scale resolution could be obtained on the surface of highly oriented pyrolytic graphite with an SWNT tip shorter than 300 nm. In the case of ring type SWNT tip, which used the side wall of SWNT, the STM images depended on the scan direction due to the half-ring shape, and atomic-scale resolution could be obtained when scanned along the circumference direction of the ring. Although the stability of the SWNT tip during scanning needs to be improved, present results prove the potential of SWNT for STM probes. [DOI: 10.1380/ejssnt.2013.105]

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The local structure of bismuth film deposited at liquid nitrogen temperature was investigated by the extended X-ray absorption fine structure (EXAFS) analysis. In the Fourier transform of EXAFS function the peak originated from the intralayer first nearest neighbor (1NN) correlation exists while that originated from the interlayer 1NN correlation disappears. This suggests that the primary structure remains but the secondary structure is disrupted. [DOI: 10.1380/ejssnt.2013.110]

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An atmospheric-pressure argon plasma jet was directly irradiated onto distilled water. Upon plasma jet irradiation, hydrogen peroxide (H₂O₂) was generated in the distilled water, and the H₂O₂ concentration increased with the duration of plasma jet irradiation. These results were obtained by semiquantitative determination using H₂O₂ test strips and by flow injection analysis (FIA). It is considered that, upon plasma jet irradiation, hydroxyl (OH) radicals are generated when high-energy electrons in a plasma jet collide with water (H₂O) molecules in distilled water and bind to each other to form H₂O₂. [DOI: 10.1380/ejssnt.2013.113]

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The kinetics of the initial oxide growth on the Si(111) surface have been investigated using real-time photoelectron spectroscopy and density functional theory (DFT) calculations. Including SiO desorption into the description of the transition from Langmuir-type adsorption to two-dimensional (2D) oxide island growth reveals that oxidation at high temperature T and low oxygen pressure P_O2 is not governed by 2D oxide island growth despite sigmoidal oxygen uptake curves. Because SiO desorption during the initial oxide growth depends strongly on temperature and oxide coverage θ_oxide in the transition region, an initial oxidation model for the transition region is proposed. According to P_O2-dependent experimental results and theoretical calculations, the frequent occurrence of SiO desorption is due to the formation of the transition state tri-ins×2 species, SiO desorption during the initial oxidation is suppressed by the most thermally stable oxygen adsorption species tri-ins×3 formed on Si(111)7×7. [DOI: 10.1380/ejssnt.2013.116]

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We investigated the influence of an external magnetic field for the carrier injection process of a metal (Au)/insulator (Cr₂O₃/FeCr/CeO₂)/semiconductor (Si) capacitor, in which the insulator consists of magnetic materials. By applying an electric field, electrons propagating through the CeO₂ layer from Si were injected into the FeCr or an oxygen deficiency layer formed around the FeCr layer. When a magnetic field was applied, the hysteresis window width of this capacitor was increased. I-V curve analyses under a magnetic field revealed that this increases was more likely due to the magnetic state of the FeCr layer. [DOI: 10.1380/ejssnt.2013.122]

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Extremely asymmetric x-ray diffraction is a powerful technique for observing minute strains near crystal surfaces. This work focused on the peak intensity of the rocking curve and studied the change in peak intensity with respect to the wavelength of x-rays using dynamical diffraction calculations. From the calculations assuming uniaxial strain along the depth direction of the crystal, it was found that the peak intensity becomes more sensitive to strain as the wavelength decreases below a critical value (critical wavelength λ_c) at which the total reflection of incident x-rays is enhanced. Comparing the profile of peak intensity vs. wavelength for a strained crystal with that for an unstrained crystal, it is clear that the introduction of compressive or tensile strain causes either enhancement or reduction of the intensity. The difference spectra generated by subtraction of the profile of peak intensity vs. wavelength for an unstrained crystal from that for a strained crystal shows a systematic change with respect to the strain parameters, the maximum strain value ε₀ and the thickness of the strained layer H. It is expected that we can evaluate the strain more quickly and easily by fitting the difference spectra than by using the rocking curves when the rocking curves are featureless. [DOI: 10.1380/ejssnt.2013.127]

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In general, scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDS) has been used in laboratories or factories for the analysis of the element distribution in the samples such as electric components. However, SEM-EDS requires sample preparation, which usually is difficult and takes a long time. On the other hand, micro X-ray fluorescence (μ-XRF) can be utilized for the elemental analysis underneath the surface of the samples thanks to the high penetrating power of X-rays. Furthermore, the depth distribution of elements in the samples can be acquired by the latest confocal XRF. In this paper, the information regarding the depth direction in small electrical and electronic components is compared for SEM-EDS, μ-XRF and the confocal XRF. At the same time, we give a brief report on not only the development of confocal XRF equipment but also some ideas as to the depth profile of the samples. [DOI: 10.1380/ejssnt.2013.133]

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Based on density functional theory, we report an initial degradation reaction before a ring-opening reaction which is a traditional degradation reaction in imidazolium-based anion exchange membranes (AEMs) and has been reported by several experimental groups. In the present work, a 1-ethyl-3-(4-vinylbenzyl) imidazolium (EVIm) monomer is focused as a part of imidazolium-based AEMs. Firstly, a hydroxide anion is put to the EVIm monomer and the geometry is optimized. Secondly, the minimum reaction path along the ring-opening reaction is calculated and it is concluded that the EVIm monomer is resistant to the ring-opening reaction because of the high energy barrier. Further, when the hydroxide anion is put near the EVIm monomer, the C-H bond at the C2 position of imidazole ring is elongated. As the result, the feasibility of a dehydrogenation reaction where the hydrogen bonding to the C2 position desorbs is suggested. Finally, in order to compare the energy barrier to that of the ring-opening reaction, the minimum reaction path along the dehydrogenation reaction is calculated. From these analyses, we propose that the dehydrogenation reaction precedes the ring-opening reaction and it is also much more dominant rather than the ring-opening reaction in the EVIm monomer. [DOI: 10.1380/ejssnt.2013.138]

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We propose a new type of multiferroic system using magnetoelectric (ME:Cr₂O₃) material/ultra-thin ferroelectric (FE) materials/a magnetoelectric material heterostructure. This ME and FE hetero system showed a general polarization-electric field hysteresis curve. When a magnetic and electric field (ME field) was applied at the same time, polarization changed depending on the LiNbO₃ thickness. This might be due to the magnetic coupling of two Cr₂O₃ layers by the ME field. [DOI: 10.1380/ejssnt.2013.89]

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We have investigated the L-cysteine adsorption reaction on the Au nanoparticles (NPs) prepared by means of the solution plasma method. The particle size of the Au NPs is estimated to be 2.4±1.0 nm as prepared. When the L-cysteine adds into the Au NPs colloidal solution, the solution color is quickly changed from red to dark blue. It is found that the adsorbates of L-cysteine thiolate, cystine and atomic sulfur exist on the Au NPs surface by sulfur K-edge NEXAFS. In addition, the Au NPs aggregate each other by the hydrogen bonding at carboxyl groups and produce the black colored precipitate. In this paper, we have revealed the adsorption behavior of the L-cysteine on the Au NPs by AFM, UV-vis, ζ-potential measurement and NEXAFS techniques. [DOI: 10.1380/ejssnt.2013.18]

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In a chemical reaction, both material conversions and energy partitioning take place simultaneously. Then its mechanism must be characterized from the viewpoints on both sides. Energy partitioning in surface reactions can be examined on product desorption processes when these are repulsive. This principle is exemplified in CO(a)+O(a) → CO₂(g) on Pd(110)(1×1), and its application is proposed for N₂O(a) → N₂(g)+O(a) on the same surface. Structural information of desorption sites and active intermediates, as well as transition states, can be delivered from desorption- and azimuth-angle dependences of physical quantities of desorbing hyper-thermal products; i.e., anisotropic distributions of their flux, and translational and internal energies. [DOI: 10.1380/ejssnt.2013.65]

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In Section III. C. “RBS Results” in Ref. [1], all fluences mentioned as “10^-15 ions/cm²”, “10^-16 ions/cm²” and “10^-17 ions/cm²” should read “10¹⁵ ions/cm²”, “10¹⁶ ions/cm²” and “10¹⁷ ions/cm²”, respectively.

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