The simultaneous realization of low thermal conductivity and high thermoelectric power factor in materials has long been the goal for social use high-performance modules. Nanostructuring approaches have drawn considerable attention because success reducing conductivity. On contrary, enhancement factor, namely, increase Seebeck coefficient electrical conductivity, difficult. We propose a method by introducing coherent homoepitaxial interfaces with controlled dopant concentration, which...

A Si-based superlattice is one of the promising thermoelectric films for realizing a stand-alone single-chip power supply. Unlike p-type (SL) achieving higher factor due to strain-induced high hole mobility, in n-type SL, strain can degrade lifting conduction band degeneracy. Here, we propose epitaxial Si-rich SiGe/Si SLs with ultrathin Ge segregation interface layers. The layers are designed be sufficiently strained, not give above Si Therein, drastic thermal conductivity reduction occurs...

For realization of new informative systems, the memristor working like synapse has drawn much attention. We developed isolated high-density Fe3O4 nanocrystals on Ge nuclei/Si with uniform and high resistive switching performance using low-temperature growth. The nuclei had a well-controlled interface (Fe3O4/GeOx/Ge) composed high-crystallinity high-quality GeOx layers. showed characteristics (high probability ~90%) relatively Off/On resistance ratio (~58). enables electric field application...

This study demonstrates a simultaneous realization of ultralow thermal conductivity and high thermoelectric power factor in epitaxial GeTe thin films/Si substrates by combination the interface introduction domain engineering suppression Ge vacancy generation point defect control. We formed Te-poor films having low-angle grain boundaries with misorientation angle close to 0° or twin interfaces 180°. The control defects gave rise lattice ∼0.7 ± 0.2 W m-1 K-1. value was same order magnitude as...

Ballistic phonon transport was observed in Si films containing Ge nanodots. In SiGe nanodots, thermal conductivity drastically reduced close to that of amorphous materials due alloy scattering and nanodot scattering.

Herein, we investigate a two-point crosslinked amyloid-β (Aβ) dimer, which forms an intermolecular β-sheet. The atomic force microscopy statistical results indicate that the heights of these dimers are approximately 0.37 nm, providing baseline for Aβ peptide sizes and improving our understanding oligomers in Alzheimer's disease.

Temporal decay characteristics of dislocation-related luminescence bands (D1–D4) were explored in strain-relieved epitaxial SiGe/Si(100). Close similarity the profiles was observed not only between D1 and D2 but also D3 D4 bands. The transients at low temperatures are characterized by long times, τ≳200 ns, whereas exhibit even sharper with τ<60 ns. Temperature dependence ‘‘radiative’’ lifetimes implies a free-to-bound nature bands, while bound-to-bound character origins for D3,

The electrochemical etching method by Ibe et al. [J. Vac. Sci. Technol. A 8, 3570 (1990)] to fabricate sharp tips for scanning tunneling microscopy was modified shortening the cutoff time of current after material wire drops off at air-electrolyte interface. tip radius measured field ion successfully reduced 8 nm when shortened 50 ns. dependence field-emitting electron from sharpest close one expected Fowler–Nordheim formula with a reasonable value emitting area tip.

Abstract Measurements of dislocation glide velocity in heteroepitaxial Si1−xGex thin films grown on Si(100) substrates revealed that the threading dislocations penetrating epitaxial layers depends almost linearly film thickness (dislocation length) very and shows saturation as exceeds about 1 μm, agreement with results a similar experiment performed by Tuppen Gibbings 1990. The activation energy motion is unaltered over this transition, which incompatible view such brought commencement kink...

The hopping movements of Cl atoms on a Si(111)-(7 x 7) surface that are enhanced by an electron injection from tips scanning tunneling microscope (STM) exhibit spatial spread the point with anisotropic distribution. effect becomes greatest at sample bias voltage being resonant Si-Cl antibonding states and also exhibits oscillatory decay distance characterized wavelength depending voltage. All these facts can be interpreted in terms coherent expansion wave packets locally formed STM tip.

A transparent thermoelectric material requires not only high performance but also optical transmittance. However, in nanostructured materials, the nanostructure interface brings trade-off relationship between thermal conductivity and We propose an approach for simultaneous control of transmittance epitaxial films, where carriers can be smoothly transported. This is realized by design based on three strategies: (1) a large atomic mass difference at heterointerface low conductivity; (2) with...

A self-assembly technique for high density (∼1 × 1011 cm−2) β-FeSi2 nanodots epitaxially grown on Si (001) substrates was developed using a codeposition method of Fe and ultrathin SiO2 films with nuclei. Photoabsorption spectra individual their photoabsorption maps at the direct-transition edge were obtained electric field modulation spectroscopy combined scanning tunneling microscopy nanometer spatial resolution.

The first application of laser-combined time-resolved scanning tunneling microscopy (STM) to single-atomic-level analysis was demonstrated. dynamics photoinduced holes, transiently trapped at the surface and recombined with electrons from STM tip in-gap states associated single-(Mn,Fe)/GaAs(110) structures, successfully probed on atomic level for time. In addition, light-modulated spectroscopy (LT-STS) performed energy–space in conjunction measurement shown useful developing techniques...

We have carried out time-resolved scanning tunneling microscopy on a layered semiconductor with an indirect bandgap, p-WSe2, and the dynamics of nonequilibrium photocurrent generated by ultrashort-pulse-laser excitation was analyzed. The reflecting flow excited photocarriers at surface, which is determined balance between diffusion rates, successfully probed. Furthermore, excess minority carriers transiently trapped surface for few nanoseconds, produce transient photovoltage cannot be...

High crystallinity Si films containing silicide nanodots (NDs) were epitaxially grown on substrates at high temperature (∼750 °C), where the phase of NDs (metallic α-FeSi2 or semiconductor β-FeSi2) was selectable by tuning Fe deposition amount. The high-temperature-grown with exhibited lower thermal conductivity (5.4 W m−1 K−1) due to phonon scattering ultrasmall ND interfaces than bulk Si-silicide nanocomposites that have ever been reported. In this system extremely low conductivity, less...

Scanning tunneling microscopic (STM) studies of C60 films deposited on highly oriented pyrolytic graphite substrates revealed that the electron injection from STM tip induces decomposition (isomerization) molecules have been polymerized also by into films. Both reaction rates were characterized a linear dependence injected current and common threshold around 2 V in sample bias dependence. We discuss two nonthermal mechanisms for polymerization reactions: electronic excitation mechanism Auger...

Spatially resolved Fourier-transform photoabsorption spectra of individual Ge1−xSnx nanodots, obtained by a technique based on scanning tunneling microscopy, exhibited distinct peak far below the absorption edge Si substrate, which showed clear blue shift with decreasing dot size. The energy position measured in high accuracy was good agreement optical transition between discrete levels theoretically predicted size dependence due to quantum-confinement effect, previously observed...

Abstract Understanding and extracting the full functions of single-molecule characteristics are key factors in development future device technologies, as well basic research on molecular electronics. Here we report a new methodology for realizing three-dimensional (3D) dynamic probe conductance, which enables elaborate 3D analysis conformational effect electronics, by formation Si/single molecule/Si structure using scanning tunnelling microscopy (STM). The robust covalent bonds between...

Alzheimer's disease is a neurologic disorder characterized by the accumulation of extracellular deposits amyloid-β (Aβ) fibrils in brain patients. The key etiologic agent not known; however oligomeric Aβ appears detrimental to neuronal functions and increases deposition. Previous research has shown that curcumin, phenolic pigment turmeric, an effect on assemblies, although mechanism remains unclear. In this study, we demonstrate curcumin disassembles pentameric oligomers made from synthetic...

Polymerization of C60 clusters epitaxially grown on Si(111)-(7×7) substrates was found to be induced by electron injection from the probe tips scanning tunneling microscopes (STM) as sample bias increased +4.0 +5.5 V, exhibiting an evolution behavior characterized incubation, a linear growth, and saturation. The incubation time growth rate are dependent greatly site, which is explained model taking into account pre-existing stress driving force polymerization internal built up consequence...