Thermal oxidation process on Si(113)-(3 × 2) investigated using high-temperature scanning tunneling microscopy.

Thermal oxidation of Si(113) in a monolayer regime was investigated using high-temperature scanning tunneling microscopy (STM). Dynamic processes during thermal oxidation were examined in three oxidation modes - oxidation, etching, and transition modes - in the third of which both oxidation and etching occur. A precise temperature-pressure growth mode diagram was obtained via careful measurements for Si(113), and the results were compared with those for Si(111) in the present work and Si(001) in the literature.

Laying down of gold nanorods monolayers on solid surfaces for surface enhanced Raman spectroscopy applications.

Laying-down gold nanorods (GNRs) of a monolayer immobilized on a solid substrate was realized with a hybrid method, a combination of three elemental technologies: surface modification, electrophoresis, and solvent evaporation. The self-assembly of CTAB-protected GNRs in the solution was induced by 0.05 mM of EDTA.

Direct observation of the Si(110)-(16×2) surface reconstruction by atomic force microscopy.

The atomic arrangement of the Si(110)-(16×2) reconstruction was directly observed using noncontact atomic force microscopy (NC-AFM) at 78 K. The pentagonal structure, which is the most important building block of the reconstruction, was concluded to consist of five atoms, while only four or five spots (depending on tip bias) have been reported with scanning tunneling microscopy (STM). Single atoms were determined to exist near step edges between upper and lower terraces, which have not been reported using STM.

Atomic layer doping of Mn magnetic impurities from surface chains at a Ge/Si hetero-interface.

We realize Mn δ-doping into Si and Si/Ge interfaces using Mn atomic chains on Si(001). Highly sensitive X-ray absorption fine structure techniques reveal that encapsulation at room temperature prevents the formation of silicides/germanides while maintaining one-dimensional anisotropic structures. This is revealed by studying both the incident X-ray polarization dependence and post-annealing effects.

Formation of Uniform and High-Coverage Monolayer Colloidal Films of Midnanometer-Sized Gold Particles over the Entire Surfaces of 1.5-in. Substrates.

We report a simple and facile method for fabricating monolayer colloidal films of alkanethiol-capped gold nanoparticles (AuNPs) on glass substrates. The new method consists of two sequential sonication processes. The first sonication is performed to obtain a well-dispersed state of alkanethiol-capped AuNPs in hexane/acetone in the presence of a substrate.

Dopant activation mechanism of Bi wire-δ-doping into Si crystal, investigated with wavelength dispersive fluorescence x-ray absorption fine structure and density functional theory.

We successfully characterized the local structures of Bi atoms in a wire-δ-doped layer (1/8 ML) in a Si crystal, using wavelength dispersive fluorescence x-ray absorption fine structure at the beamline BL37XU, in SPring-8, with the help of density functional theory calculations. It was found that the burial of Bi nanolines on the Si(0 0 1) surface, via growth of Si capping layer at 400 °C by molecular beam epitaxy, reduced the Bi-Si bond length from [Formula: see text] to [Formula: see text] Å. We infer that following epitaxial growth the Bi-Bi dimers of the nanoline are broken, and the Bi atoms are located at substitutional sites within the Si crystal, leading to the shorter Bi-Si bond lengths.

Spatially Uniform Thin-Film Formation of Polymeric Organic Semiconductors on Lyophobic Gate Insulator Surfaces by Self-Assisted Flow-Coating.

Surface hydrophobization by self-assembled monolayer formation is a powerful technique for improving the performance of organic field-effect transistors (OFETs). However, organic thin-film formation on such a surface by solution processing often fails due to the repellent property of the surface against common organic solvents. Here, a scalable unidirectional coating technique that can solve this problem, named self-assisted flow-coating, is reported.

Nonvortical Rashba Spin Structure on a Surface with C_{1h} Symmetry.

A totally anisotropic peculiar Rashba-Bychkov (RB) splitting of electronic bands was found on the Tl/Si(110)-(1×1) surface with C_{1h} symmetry by angle- and spin-resolved photoelectron spectroscopy and first-principles theoretical calculation. The constant energy contour of the upper branch of the RB split band has a warped elliptical shape centered at a k point located between Γ[over ¯] and the edge of the surface Brillouin zone, i.e.

Assembly of Mid-Nanometer-Sized Gold Particles Capped with Mixed Alkanethiolate SAMs into High-Coverage Colloidal Films.

We investigated the influence of the mixed n-alkanethiolate self-assembled monolayer (SAM) formed on gold nanoparticles (AuNPs: 50.0 ± 3.2 nm in diameter) on their assembly into colloidal films.

Selective Two-Photon-Absorption-Induced Reactions of Anthracene-2-Carboxylic Acid on Tunable Plasmonic Substrate with Incoherent Light Source.

In this research, we report the development, characterization and application of various plasmonic substrates (with localized surface plasmon resonance wavelength tunable by gold nanoparticle size) for two-photon absorption (TPA)-induced photodimerization of an anthracene derivative, anthracene carboxylic acid, in both surface and solution phase under incoherent visible light irradiation. Despite the efficient photoreaction property of anthracene derivatives and the huge number of publications about them, there has never been a report of a multiphoton photoreaction involving an anthracene derivative with the exception of a reverse photoconversion of anthracene photodimer to monomer with three-photon absorption. We examined the progress of the TPA-induced photoreaction by means of surface-enhanced Raman scattering, taking advantage of the ability of our plasmonic substrate to enhance and localize both incident light for photoreaction and Raman scattering signal for analysis of photoreaction products.

Enhanced catalytic activity of self-assembled-monolayer-capped gold nanoparticles.

An unprecedented substrate-selective catalytic enhancement effect of an alkanethiol-self-assembled monolayer (SAM) on Au nanoparticles (AuNPs) is reported. In the supported 2D-array of AuNPs, the alkanethiol-SAM acts as a protein-like soft reaction space in which the substrate molecules are encapsulated through non-covalent intermolecular hydrophobic interactions, and thus catalytic reactions are accelerated at AuNP surfaces.

Electronic structure of Bi lines on clean and H-passivated Si(100).

By means of scanning tunnelling microscopy and spectroscopy, we have investigated the electronic structure of Bi nanolines on clean and H-passivated Si(100) surfaces. Maps of the local density of states (LDOS) images of the Bi nanolines are presented for the first time. The spectra obtained for nanolines on a clean Si surface and the LDOS images agree with ab initio predicted spectra for the Haiku structure.

Design, synthesis, and complementary recognition of beta-hairpin peptides stabilized by artificial DNA base-pairing amino acids.

A novel DNA base-pairing beta-hairpin peptide involving intramolecular hydrogen bonds for induction of beta-hairpin secondary structure and intermolecular complementary hydrogen bonds between thymine and diaminopyridine for molecular recognition has been synthesized.

Highly localized light field on metallic nanoarrays prepared with DNA nanofibers.

We have reported a one-step method for creating one-dimensional metallic nanoarrays on surfaces. This method is based on the processes of solvent vapor-induced buildup and controlled drying front movement, and forms parallelly aligned metallic nanoarrays exceeding several hundred micrometers in length on a poly(dimethylsiloxane) (PDMS) sheet. Strong light scattering originating from highly localized electromagnetic (light) fields was observed on prepared metallic nanoarrays.

Simple one-step growth and parallel alignment of DNA nanofibers via solvent vapor-induced buildup.

This communication describes the growth and parallel patterning of 1D DNA nanofibers, exceeding several hundred micrometers in length and 40 nm in diameter, induced by solvent evaporation.

Racemic (RS(C),SR(S))-(2-{[1-allyl-oxy-carbonyl-3-(methyl-sulfanyl)prop-yl]iminometh-yl}phenyl-κS,N,C)chlorido-platinum(II).

The title compound, [Pt(C(15)H(18)NO(2)S)Cl], was obtained by the cyclo-metallation reaction of cis-bis-(benzonitrile)dichlorido-platinum(II) with N-benzyl-idene-l-methio-nine allyl ester in refluxing toluene. The Pt(II) atom has a square-planar geometry and is tetra-coordinated by the Cl atom and the C, N and S atoms from the benzyl-idene methio-nine ester ligand. In the crystal structure, the S atoms show opposite chiral configurations with respect to the α-carbon of the methio-nine, reducing steric repulsion between the methyl and allyl ester groups.

Alignment-induced epitaxial transition in organic-organic heteroepitaxy.

We report the epitaxial growth of thin films of a small organic molecule (pentacene) on polymer substrates with controllable photoalignment over a wide range. The pentacene molecular plane exhibited a distinct orientational change from parallel to perpendicular relative to the polymer chain with increasing substrate polymer alignment. Each orientation consists of twinlike domains.

Defective continuous hydrogen-bond networks: an alternative interpretation of IR spectroscopy.

We apply our previously developed deconvolution method and interpretation to analyze changes in the OH stretching band [nu(OH) band] of low-concentration (< or =0.2 m) aqueous solutions of NaCl and KCl. We treat these simple, monovalent ions as defects in the hydrogen-bond network of pure water and quantify the changes in the spectra at low defect concentration with an "order parameter".

Structural correlations in liquid water: a new interpretation of IR spectroscopy.

We present a new and alternative interpretation of the structure of the IR vibrational mode (nu(OH) band) of pure water. The re-interpretation is based on the influence of the cooperative hydrogen bonding arising from a network of hydrogen bonds in the liquid. The nu(OH) band has six components that are dominated by differences in their O-H bond lengths but deviate from thermodynamically average values due to interactions with the hydrogen bond network.

Light exposure dependence of molecular orientation of glassy polyfluorene layers formed on photo-aligned polyimide films.

We have investigated the molecular orientation of glassy poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) layers formed on photo-aligned polyimide films with different in-plane anisotropy. The polyimide contains azobenzene in the backbone structure (Azo-PI), allowing us to control the in-plane anisotropy of the film by varying linearly polarized light (LP-L) exposure. The glassy PFO layers (approximately 30 nm thick) were obtained by annealing the samples at the liquid crystalline phase of PFO and then quenching them to room temperature.

Selective growth of ag nanowires on Si(111) surfaces by electroless deposition.

Electroless deposition of Ag on atomically flat H-terminated Si(111) surfaces in aqueous alkaline solutions containing Ag ions produced two different sizes of Ag nanowires along atomic step edges: (1) a narrow nanowire of 10 nm in width and 0.5 nm in height and (2) a wide nanowire of 35 nm in width and 11 nm in height. The narrow and wide nanowires were formed by immersion in the solutions containing less than 1 ppb and 8 ppm dissolved-oxygen concentrations, respectively.

Behaviors of surfactant atoms on Si(001) surface.

The behaviors of surfactant atoms for thin film growth on the Si(001) surface formed by molecular beam epitaxy were observed. At first, heterointerfaces on Si/Ge and Ge/Si without surfactant effect were investigated and are discussed on the basis of thermodynamics of surfaces and surface diffusion. The mechanism of island formation as a later stage of Stranski-Krastanov growth mode is also discussed.