In this report, we show an improved method for the simultaneous measurement of optical and electrical properties of single-channel proteins for analysis of the gating mechanism. Large-conductance Ca²⁺-activated potassium (BK) channels were isolated from porcine uterine smooth muscle and labeled with Cy5 via antibody against the N-terminal. These Cy5-labeled BK channels were incorporated into lipid bilayer membranes followed by single channel current measurements. Cy5-labeled BK channels possessed Ca²⁺ and voltage sensitivity. The orientation of the vesicles was determined to be outside-out. Charybdotoxin applied from the cis side blocked the channel current. For stable observations of ligand and channel binding, BK channel immobilization was also examined. The lateral diffusion coefficient of BK channels decreased over 200 fold in 1 μ annexin V while the open probability did not change. This study is a significant advancement in simultaneous measurements of ligand binding and current change at the single channel level. [DOI: 10.1380/ejssnt.2007.1]

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We propose a detailed method of preparing immobilized gold nanoparticles on a substrate for application to dielectric sensors. We show the relationship between the amount of aminofunctional silane on the substrate and the absorbance caused by localized surface plasmon resonance of the gold nanoparticles. The amount of silane was changed by controlling rinsing time with distilled water. In the rinsing process, two features of dispersion for isolated nanoparticles on the substrate were observed. One was a high density of nanoparticles, but with some of them incompletely isolated; the other was a low density of nanoparticles, but all completely isolated. To confirm the suitability for sensor applications, we measured the absorption spectra of the substrates surrounding media of various dielectric constants. [DOI: 10.1380/ejssnt.2007.74]

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We have investigated the effect of chemical state control of the Si substrate surfaces for the formation of low-defective uniform supported lipid bilayers. To form supported lipid bilayers, we used the vesicle fusion method. In the bilayer formation processes, control of the interfaces between the vesicles and the surfaces is important. To examine the effect of the oxide formation process on Si surfaces, we used SiO₂ surfaces prepared by chemical acid-treatment and those by thermal oxidation. SiO₂ surfaces are generally hydrophilic. To change the chemical state of the SiO₂ surfaces, they were modified with various self-assembled monolayers. These surfaces were immersed in a solution with lipid vesicles suspension, and the lipid vesicles were transformed into planar bilayers. The hydrophilic surface is more suitable for the uniform lipid bilayer formation than the hydrophobic surface. The bilayer coverage on the thermal oxide surface is larger than that on the chemical oxide one. These results indicate that the surface chemical states influence the efficiency of the supported lipid bilayer formation. [DOI: 10.1380/ejssnt.2007.99]

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Surface atom evaporation under electron field emission was investigated by scattering-state calculations based on the density-functional theory. We found that surface atom evaporation assisted by electron field emission occurs for a certain electric-field strength that is lower than that of usual field evaporation without electron field emission. The present ab-initio study elucidates the surface atom process under field emission, which has been frequently observed in experiments, for the first time. [DOI: 10.1380/ejssnt.2007.106]

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X-ray diffraction (XRD) measurements were carried out in order to investigate the structure of bismuth nanoparticles. The x-ray diffraction profile of the as-deposited sample has broad peaks originated from Bi nanoparticles. The peaks become sharp and the intensities increase with annealing at 300°C. A halo pattern was extracted from analysis of background in the as-deposited samples. The existence of the halo pattern implies that the as-deposited nanoparticles contain of the amorphous phase. [DOI: 10.1380/ejssnt.2007.110]

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The solid-solid interface between NaCl substrate and KCl deposit crystals of a NaCl-KCl combined crystal which was created in the NaCl-KCl-H₂O ternary system was observed. It was assumed that the NaCl-KCl interface had different physical properties from pure NaCl or pure KCl crystal. In order to discuss the formation process and the physical property of the NaCl-KCl interface experimentally, an atomic force microscope (AFM) was applied to observation and analysis. After cleaving the combined crystal, the influence of moisture in the air to the solid-solid interface between NaCl and KCl was examined by controlling humidity. The force-vs.-distance curve of AFM was measured as the line analysis on the cleaved crystal. As the result, it became clear that the NaCl-KCl interface was easily damaged by the moisture in the air. [DOI: 10.1380/ejssnt.2007.113]

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By first-principles calculations for NO adsorbed on Pt(111) surface, we found strange behaviors of peak intensities in vibrational spectra of high-resolution electron energy loss spectroscopy (HREELS) and infrared reflection absorption spectroscopy (IRAS). For NO/Pt(111) at a high coverage, the peak intensity of fcc-hollow species is about 10 times smaller than that of atop species, although the numbers of both species on the surface are equal. By analyzing the charge density distributions, it was found that an electron transfer between the NO molecule and the surface Pt atom at the atop site takes place as the N-O bond at the fcc-hollow site vibrates, resulting in a screened dynamic dipole moment.[DOI: 10.1380/ejssnt.2007.122]

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We present results of theoretical simulations of atomic force microscopy (AFM) for the systems consisting of a graphite flake on a graphite substrate with a diamond tip. How are atomic sliding motions of the sample reflected on AFM images? This central issue was investigated by changing tip height and size of the flake which was located on the substrate surface and placed in a vacancy on the surface. When the tip height becomes higher, the flake motion induced by the tip changes from the swinging motion centered at one local potential minimum to the slipping motion between local potential minima. At the same time, the image changes from the one reflecting flake feature to the one reflecting surface feature. When the flake size changes, the inverse of image contrast is seen. When the flake is in a small vacancy, a ring shaped image is seen, which reflects the rotational motion of the flake induced by the tip motion. When the flake is in a large vacancy, the image is a combination of a ring shaped one and a noisy ribbon like one caused by the lateral movement of the flake. [DOI: 10.1380/ejssnt.2007.126]

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We present a model of spatial distribution of electrons, holes, clusters of intrinsic and admixtures (defects of different types) in nanostructured semiconductor thin films. We obtain intermittent, heterogeneous distributions of concentration typical for images of surfaces obtained by scanning tunneling microscopy, atomic-force microscopy and electron microscopy by numerical analyses.[DOI: 10.1380/ejssnt.2007.132]

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Based on the measurements of emission angle and photon energy dependences of Auger electron intensity by using a display-type analyzer, two-dimensional X-ray Auger resonance emission spectroscopy (2D-XARES) method for depth resolved analysis of atomic and electronic structures has been developed. Here we applied this method to analyze the hole distribution at the surface region of high-transition-temperature cuprate superconductor (Bi2212). The crystalline quality at each point on the sample surface was evaluated by Cu LMM Auger emission angular distribution (AEAD). Cu L-edge X-ray absorption spectra, especially the resonance peak structure of Cu 3d_x^2-y^2 at absorption edge were shown to be quite sensitive to the surface quality. By combining AEAD with XANES, i.e. 2D-XARES, the vertical distribution of Cu 3d_x^2-y^2 hole state at the surface region in conjunction with crystalline quality was revealed. [DOI: 10.1380/ejssnt.2007.143]

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Density functional theory calculations have been performed on Fe-only hydrogenase analogues compounds [(i-PDT)Fe₂(CO)₄(CN)₂]^2- (compound I) and [Fe₂(CO)₄MeSCH₂C(Me)-(CH₂S)₂}(CN)]^- (compound II). Results using BPW91/6-311+G(d,p) show electron affinity and trends in molecular orbitals consistent with photoelectron spectroscopy data. The HOMO orbitals show familiar Fe-Fe bonding characteristics while the LUMO orbitals show Fe-Fe anti-bonding characteristics. To compare the effects of a second CN versus a terminal sulfur ligand, results for compound I after one electron is removed (compound I—1e) were compared with those of compound II. It was found that compound I—1e has a much lower HOMO. Mulliken charge analysis also shows that the terminal sulfur has a stronger electron donating effect than a CN ligand. From the standpoint of computational materials design, we therefore think that similarities in electron affinity, 2Fe charge density and HOMO/LUMO characteristics to the biologically present active site should be bases for predicting catalytic activity of Fe-only hydrogenase analogues. [DOI: 10.1380/ejssnt.2007.148]

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Thin films of cadmium stannate (Cd₂SnO₄) have been deposited on glass substrates by pulsed Nd:YAG laser at room temperature. The deposited film was crystalline in nature and highly oriented in the (311) direction. Using this method, Cd₂SnO₄ films with the Hall mobility of 25 cm² V^-1 s^-1 and the carrier concentration of 6× 10²⁰ cm^-3 corresponding to the conductivity of 2.4× 10³ S cm^-1 have been prepared without post-deposition thermal annealing. The films exhibited average optical total transmission of 70% in the visible region. The optical band gap was found to be 3.18 eV. [DOI: 10.1380/ejssnt.2007.152]

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We investigate the transport properties of a single quantum dot Aharonov-Bohm (AB) interferometer by analyzing the total current of the system in and out of the Kondo regime. We then interpolate the transport behavior of the AB interferometer in the linking regime. We show the explicit expression of the Kondo temperature as a function of the AB phase together with its dependence on other characteristics such as the linewidth of the ring, the finite Coulomb interaction and energy levels of the quantum dot. The total current as a function of AB phase and the ratio of temperature to the Kondo temperature of the system is also presented in this work. [DOI: 10.1380/ejssnt.2007.29]

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Oriented crystal fibers of pentacene were produced by a simple casting process from trichlorobenzene solution at elevated temperature. The solution was placed in the air gap between a glass roller and a glass substrate. The width of the air gap was determined by a Teflon spacer wound around both ends of the roller. The roller was moved over the substrate with a constant speed and crystal fibers with approx. 100 nm height, micrometer width and a length of up to 100 μm were formed in the rolling direction. The fibers were characterized by optical microscopy and scanning electron microscopy. [DOI: 10.1380/ejssnt.2007.103]

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The results of spin-polarized density functional theory calculations for O₂ dissociative adsorption on Pt monolayer on Fe(001) (Pt_ML/Fe(001)) structure are presented and are compared with that of Pt(001). The potential energy curves for the reaction of Pt with O₂ as a function of O₂ center-of-mass distance from the platinum layer and O-O interatomic distance show that Pt_ML/Fe(001) produces a combination of lower activation barrier for O₂ dissociation and weaker O-atom binding which are both beneficial for a easier O₂ dissociation to produce adsorbed O and for subsequent reactions of O with other surface species for O₂ reduction process. Local density of states at Pt surface shows induced spin polarization on the Pt atomic layer characterized by d_zz peak at the Fermi level, in good agreement with experimental findings. Such effect increases unfilled d_zz orbital on Pt surface modifying Pt electronic surface structure towards a favorable O₂-Pt d interaction. Decrease in the magnetic moments of O and Pt atoms upon O adsorption indicates an antiparallel O unpaired electron spin alignment with Pt spin rendering consequent stabilization and a lowering of energy cost to O₂ activation. On the other hand, the weaker O binding reflects the stronger Pt-Fe interlayer bonding typical for such bimetallic systems. [DOI: 10.1380/ejssnt.2007.117]

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We present a method to prepare tungsten tips for use in multi-tip scanning tunneling microscopes. The motivation behind the development comes from a requirement to make very long and conical-shape tips with controlling the cone angle. The method is based on a combination of a “drop-off” method and dynamic electrochemical etching, in which the tip is continuously and slowly drawn up from the electrolyte during etching. Its reproducibility was confirmed by scanning electron microscopy. Comparison in tip shape between the dynamic and static methods was shown. [DOI: 10.1380/ejssnt.2007.94]

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Optical and magnetic properties are studied on Rb and Cs clusters incorporated into the cages of aluminosilicate zeolite A (structure type code LTA), where α and β cages with inside diameters of ∼1.1 and ∼0.7 nm, respectively, are arrayed in a simple cubic structure. The average number of guest alkali atoms per α cage, n, was changed from dilute loading to ∼5 and ∼3.5 for Rb and Cs, respectively. At n > 2, the absorption coefficient at mid-infrared region increases significantly. This is assigned to a contribution of the Drude term in a metallic phase. The change from insulating phase to the metallic one is ascribed to a wider bandwidth of the 1p state of clusters compared with that of the 1s state. All samples show Curie-Weiss law with negative Weiss temperatures. In Rb clusters, both of the Curie constant and the absolute value of Weiss temperature gradually increases with increasing n at n > 2, and ferromagnetic properties are clearly found at n > 4. This n-dependence is essentially different from that in ferromagnetism in K clusters at n > 2. Cs clusters shows quite small values of Curie constant at n > 2 and also non-ferromagnetic behavior up to the maximum value of n. [DOI: 10.1380/ejssnt.2007.6]

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We have placed a multi-walled carbon nanotube (MWNT) on a pair of nano-gapped electrodes and measured its AC impedance at room temperature for frequencies up to 200 kHz. The real part of the impedance ReZ displayed no characteristic features while the imaginary part ImZ exhibited a transition from capacitive to inductive behaviors around 50 kHz. Both ReZ and ImZ spectra show no substantial changes with varying the electrode gap distance and changing the atmosphere from air to vacuum. On the other hand, upon increasing the DC bias. the whole ImZ spectral curve shifts upward to higher impedances while ReZ displays little bias dependence. We found that the inductive behavior of ImZ above 100 kHz has a negative correlation with the low-bias DC conductance of MWNTs, which approximately represents the contact conductance between MWNTs and the electrodes. This result indicates that the MWNT-electrode interface determines the inductive part of ImZ. [DOI: 10.1380/ejssnt.2007.12]

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For the perovskite-type cobalt fluoride of KCoF₃, cluster model calculations based on the spin-polarized Hartree-Fock (UHF) and hybrid-density functional theory (HUDFT) methods have been performed. It has the slightly tetragonally distorted structure, where cobalt is octahedrally surrounded by fluorine’s. In this study, we have examined the spin states under consideration of the ligand field effect, from the viewpoints of the spin density, charge density, total energy and effective exchange integral. [DOI: 10.1380/ejssnt.2007.17]

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In order to clarify the relationship between the structural distortion and variation of magnetism in the perovskite-type transition metal fluorides of KFeF₃ and RbFeF₃, we have performed cluster model calculations by the spin-polarized hybrid-density functional theory (HUDFT) method. As the rhombohedral and tetragonal distortions occur in KFeF₃ and RbFeF₃, we have obtained the effective exchange integral (J_ab) values, changing the rhombohedral angle and iron-fluorine distance, respectively. [DOI: 10.1380/ejssnt.2007.20]

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We have prepared extremely small functionalized nanoparticles (NPs) and showed that they could be introduced into living cells without modification (e.g. cationic coating) to enhance endocytic internalization. However, the internalization depended on physical adsorption of the particles on the cell surfaces, and therefore the internalization process was nonselective. Here, we prepared NPs conjugated with folic acid and a coumarin fluorophore so that the NPs (d = 2.6 nm) would be recognized by folate receptors on the cell surface. The presence of the folic acid and coumarin on the surface of the NPs was confirmed by Fourier transform infrared spectroscopy. The modified NPs were internalized by human pharyngeal cancer cells (KB cells) after an incubation time that was short compared with the time required for internalization of NPs without folic acid. This result indicates that the folic acid receptor on the KB cell membrane recognized the folic acid-conjugated NPs. Cellular recognition of NPs may lead to the development of cell-specific delivery systems. [DOI: 10.1380/ejssnt.2007.23]

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We developed an open-air type atmospheric pressure plasma machining system for fabricating the ultra-precision optical components or for finishing the functional materials. In the case of the atmospheric pressure plasma, high density plasma region is localized in the vicinity of the electrode because of its small mean free path. Therefore, free figuring without mask pattern is realized by scanning the localized reactive area. And the plasma process is insensitive to the external vibration compared with the conventional mechanical machining process, because the plasma process is a non-contact process. Furthermore, expensive utilities, such as a process chamber or a vacuum pump, are not necessary, so that a cost-effective ultra-precision machining system can be constructed. We applied this system for finishing the thin AT cut quartz crystal wafer which was manufactured by conventional mechanical cutting, lapping and polishing. As a result of the correction machining of the thickness distribution, we achieved thickness uniformity of 50 nm level by one application of the proposed process. [DOI: 10.1380/ejssnt.2007.41]

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Generation and control of quantum entanglement are studied in an equivalent-neighbor system of spatially-separated semiconductor quantum dots coupled by a single-mode cavity field. Generation of genuinely multipartite entanglement of qubit states realized by conduction-band electron-spin states in quantum dots is discussed. A protocol for quantum teleportation of electron-spin states via cavity decay is briefly described. [DOI: 10.1380/ejssnt.2007.51]

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Nanotechnologies to allow the nondisruptive introduction of carriers in vivo have wide potential for therapeutic delivery system. Iron oxide (γ-Fe₂O₃) nano-magnetic particles (NMPs) were functionalized by silanization with (3-aminopropyl)triethoxysilane. For the purpose of functionalizing the surface of the particles with amino groups for subsequent cross-linking with pharmaceuticals and biomolecules. We have evaluated physical characterization of obtained NMPs by Fourier transform infrared spectroscopy, a superconducting quantum interference device, X-ray diffraction and transmission electron microscopy to confirm particle preparation. The particles were successfully introduced into living cells without any further modification to enhance endocytic internalization, such as the use of a cationic help. Furthermore, the functionalized NMPs were conjugated with an amino acid via a cross-linker, N-(ε-maleimidocaproyloxy) sulfosuccinimide ester, with the goal of selective uptake of NMPs by cells. To confirm the amino acid modification of the NMPs, the amino acid-conjugated NMPs were labeled with a fluorescent reagent (dansyl chloride), and the fluorescence was observed by confocal laser scanning microscopy. The amino acid-conjugated NMPs have great potential for use in cell-selective delivery systems involving amino acid transporter proteins. [DOI: 10.1380/ejssnt.2007.60]

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The (1 × 1) and (√3 × √3) phases of the Pb/Si(111) surface are investigated at room temperature using non-contact atomic force microscopy. The topographic height difference between these phases is determined to be 1.6±0.1 Å, which is larger than the theoretical value (1.2 Å) previously predicted. Kelvin probe force microscopy measurements show that the work function on the (1 × 1) region is 201±16 meV higher than that on the (√3 × √3) region. The effective dipole moments by electron transfer from the first layer Si atom to the Pb adatom on the (1 × 1) phase is discussed. We also succeed in obtaining atomically resolved images of the two phases, and demonstrate that the (1 × 1) phase has small atomic corrugation compared with the (√3 × √3) phase when imaging at same tip condition and the same acquisition parameters. [DOI: 10.1380/ejssnt.2007.67]

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The surface energy band diagrams and the electron affinity of hydrogen-terminated and oxygen-terminated highly phosphorous-doped single crystal diamond (111) surfaces have been studied by ultraviolet photoelectron spectroscopy, secondary electron spectroscopy, X-ray photoelectron spectroscopy and photoemission electron micro-spectroscopy. A hydrogen-terminated boron-doped diamond (001) surface was used as a reference of surface energy band diagram. The electron affinity of the H-terminated heavily P-doped diamond was determined to be 0.2 ± 0.15 eV, thus close to zero. The electron affinity of the O-terminated highly P-doped diamond was determined to be 0.0 ± 0.15 eV, thus can be negative. However, the surface energy bands for the two highly P-doped samples were found to have large amounts (3 eV) of upward bending toward surface. [DOI: 10.1380/ejssnt.2007.33]

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Kinetics of structure and phase constitution of Fe/SiO₂/Si(001) system under different conditions of deposition and annealing was considered. It was established that SiO₂ layer is not destroyed during Fe deposition process over the temperature range from 20 to 650°C. As a result, the Fe films having different morphologies are formed on the oxide surface. Destruction of SiO₂ layer occurs upon annealing on defect places of SiO₂ film that results in the interaction of Fe atoms with the Si substrate and successive silicides formation. [DOI: 10.1380/ejssnt.2007.45]

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The review of the studies of GaAs and GaN surfaces performed by the authors at the Institute of Semiconductor Physics (Novosibirsk) are presented. The results of these studies are used for further elucidation of the physics of photoemission from the surfaces with negative electron affinity (NEA) and improving the performance of NEA-photocathodes. In particular, the requirements to III-V semiconductor surfaces, which are necessary for the preparation of NEA photocathodes with ultimate parameters, are analyzed. To meet these requirements, the experimental procedures aimed at preparing atomically clean and flat surfaces with certain reconstructions, which are subsequently activated to the state of NEA in ultra-high vacuum by coadsorption of cesium and oxygen, are developed. The surface morphological, structural, and electronic phenomena occurring on various stages of these preparation procedures are studied, and the relation of these phenomena to the physical limits of NEA-photocathode performance are discussed. [DOI: 10.1380/ejssnt.2007.80]

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Reaction between deposited Ca layers and the Si(111) substrate has been studied by metastable-induced electron spectroscopy (MIES) and low-energy electron diffraction (LEED). When a Ca-deposited (about 1ML) Si(111) surface was annealed at temperatures in the range 470-570 K, the MIES spectrum showed a peak, named P_s, at a binding energy of about 7 eV which is assigned to be an isolated Si3s state. By referring electronic structure calculations for the bulk Ca-silicides, we confirmed that a solid-phase reaction at the Ca/Si interface to induce Ca₂Si-like phases takes place at rather low annealing temperatures around 570 K. When Ca-covered (about 0.6 ML) Si(111) surfaces were annealed at temperatures in the range 770-870 K, the LEED showed 2× 1, 5× 1 and quasi-3× 2 reconstructions, depending on the temperature. We obtained MIES spectra from these surfaces involving spectral features which reflect local atomic structures of those Ca+Si surface phases. Correlations between the local atomic structure and the electronic structure probed by the MIES are discussed. [DOI: 10.1380/ejssnt.2007.89]

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The investigation of the codeposition process of iron and silicon (at a ratio of 1:2) on SiO₂/Si(001) surface was carried out at various substrate temperatures. A thin dioxide silicon layer (∼1 nm) was formed on Si(001) substrate by wet chemical treatment. It was found that the codeposition at room temperature results in the growth of continuous disordered film. Codeposition at 470°C initiates the interaction of Fe and Si atoms with each other on SiO₂/Si(001) surface and the formation of β-FeSi₂ polycrystalline film. At an increase of the codeposition temperature Si atoms interact with the SiO₂ layer. So, at 650°C some part of deposited silicon is consumed on the formation of voids in defect regions of SiO₂ layer and of three-dimensional (3D) epitaxial Si islands in these voids. Remaining part of adatoms is consumed on iron silicide formation. At 700°C all deposited silicon atoms are consumed on SiO₂ layer decomposition. In that way Fe atoms react with only bare silicon surface that leads to growth of 3D epitaxial α-FeSi₂ islands. It was investigated the influence of high temperature annealing on structural-phase composition of films deposited at various substrate temperatures. [DOI: 10.1380/ejssnt.2007.136]

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