We have elucidated the polymer adsorption layer structure in filler-rubber systems by conducting spin-contrast-variation small-angle neutron scattering (SANS) on partially and fully swollen filler-rubber samples with and without a silane coupling agent. In spin-contrast-variation SANS, dynamic nuclear polarization (DNP) was used to polarize protons and change their scattering length with respect to polarized neutron beams significantly. SANS measurements were performed in dynamically polarized states using a DNP cryostat (1.2 K and 3.35 T). From SANS profiles obtained at various proton spin polarizations, partial scattering functions (PSFs) for each component were separated by regarding each sample as a three-component system composed of silica, polymer and deuterated toluene. To analyze the obtained PSFs in detail, we built a structure model for the silica aggregates and the surrounding polymer adsorption layer. Numerical calculation based on this model successfully reproduced the experimentally obtained PSFs, providing the structural parameters of the silica aggregates and polymer adsorption layer. The results showed a considerable difference in structural parameters between the partially and fully swollen states. For the sample with the silane coupling agent, the thickness of the polymer adsorption layer decreased as the solvent fraction increased. The difference in polymer volume fraction between the polymer adsorption layer and the outside matrix was very small in less swollen states but significant in the fully swollen state. Furthermore, the scattering contribution of the polymer chains in the solvent was accurately separated via contrast variation. In the swollen silica-filled rubber without the silane coupling agent, the size of the polymer-dense regions was almost constant, regardless of the swelling ratio. By contrast, in the swollen silica-filled rubber with the silane coupling agent, the size of the polymer-dense regions significantly increased by a factor of 2 with an increase in the swelling ratio.

Control over plasmonic properties and local electric field enhancement has become an essential aspect of many modern technologies. Here we investigate these phenomena in graphene / hexagonal boron nitride (G/h-BN) heterostructures positioned on silicon (Si) and silicon dioxide (SiO2) substrates. Using finite element method for physics-based simulations of radio-frequency (RF) fields in optical range, we analyze electric field at the edges, on the flakes, and in the surrounding regions of the G/h-BN heterostructures. The results demonstrate that the electric field distribution around and within the heterostructure is strongly dependent on the thickness of graphene and h-BN flakes. The highest electric field amplification and focusing occurs at the G/h-BN edge for h-BN thicknesses between 80 and 100 nm on the Si substrate. In contrast, the SiO2 substrate substantially reduces overall field intensity in the G/h-BN heterostructures in comparison to the Si and reference structure without h-BN. These findings provide a consistent theoretical explanation for previously reported experimental Raman spectroscopy data on G/h-BN heterostructures and corroborate the model of localized charge carrier accumulation at the nanoscale G/h-BN edges on Si substrates. Furthermore, the study provides predictions for optimal excitation frequencies and for tailoring graphene plasmonic features in visible spectral range with the use of diamond and other CMOS compatible materials.

According to a scheme of room-temperature transesterification [S. Tanaka et al. Green Chem. 2021, 23, 9412-9416.], a polyethylene terephthalate (PET) film was chemically decomposed, and its surface structure was inspected by using scanning electron microscopy (SEM) and X-ray grazing incidence small-angle scattering (XGSAS), covering small-angle scattering (SAXS) and diffraction (XRD). In the reaction solution mixed with dimethyl carbonate (DMC), the decomposed fragments of ethylene glycol (EG) are immediately converted to ethylene carbonate (EC) (chemical-trap effect) so the decomposition reaction continuously proceeds forward at room temperature. After 3 days of reaction, SEM elucidated that the amorphous regions are dominantly degraded, and stripes of crystalline bundles remain on the film surface. The degraded fragments, i.e., dimethyl terephthalate (DMT) monomer or its oligomers, immediately form the cauliflower-like granule (600 nm in diameter) composed of primary clusters (40 nm in diameter), which are connected in a line and emanate from a core of the granule (referred to as the "Pot & Sugar" structure). Thus, DMT cannot be backward polymerized again (physical trap effect). In an in situ or ex situ manner, X-rays irradiated at a grazing angle to the film surface elucidated that the crystallinity at the film surface apparently increases, and small-angle scattering originating from the primary clusters of DMT appears on the surface. Although methanol, a key reagent, is a poor solvent for PET, it diffuses into the amorphous region on the film surface and more easily from the edge surface than the film surface. The swelling behavior at the film surface was accelerated by decomposition (reaction absorption).

n-Type diamond semiconductors can be fabricated by phosphorus doping via chemical vapor deposition (CVD), which is a crucial process for advancing diamond-based electronic and quantum technologies. Among various CVD techniques, hot-filament CVD is a promising method for producing n-type diamond, particularly for heavy doping, due to its simplicity and scalability. To effectively utilize this method, a comprehensive understanding of the resulting crystal quality and impurity behavior is required. In this study, we performed the epitaxial growth of n-type diamond films with phosphorus concentrations on the order of 10(18) cm(-3) by hot-filament CVD and characterized their crystal quality and phosphorus donor states through cathodoluminescence (CL) analysis. Hall effect measurements confirmed n-type conductivity of the films regardless of hydrogen concentrations (similar to 10(18) and similar to 10(19) cm(-3)). CL analysis revealed that the films exhibited luminescence from excitons bound to phosphorus donors in the near-band-edge region, indicating the formation of high-quality n-type diamond. Notably, the film with high hydrogen concentrations (similar to 10(19) cm(-3)) exhibited a spectral shift of exciton peaks toward lower photon energies along with the disappearance of fine structures, and the emergence of band-A emission in the visible-light region. These findings suggest that a large number of hydrogen atoms are associated with crystal defects and do not fully inactivate phosphorus donors.

Ultrathin single-crystal diamond (SCD) resonators offer exceptional potential for high-performance nanoelectromechanical systems (NEMS), but achieving sub-100 nm thickness with low dissipation remains a major fabrication challenge. In this work, we develop a smart-cut-assisted thinning strategy to reliably fabricate SCD cantilevers with thicknesses down to ~50 nm, representing the thinnest SCD NEMS cantilever achieved to date. Operating from 10 kHz to 3 MHz, these devices exhibit high-quality factors (∼5 × 104 at room temperature and ∼6 × 103 at 773 K). The resulting ultrathin resonators exhibit controllable geometries with resonance frequencies that closely follow the Euler-Bernoulli beam model, confirming high structural integrity. The cantilevers demonstrate robust thermal stability, with a low temperature coefficient of frequency of -10 ppm/K. As a result, the ultrathin diamond cantilevers yield a force sensitivity of ∼10-17 N/Hz1/2 and a mass resolution of ∼5.89 × 10-20 kg, close to that of a carbon nanotube cantilever. This work establishes the strategy for batch fabrication of ultrathin SCD NEMS resonators as a highly promising platform for next-generation high-sensitivity and robust nanomechanical sensing.

The nano-sized graphene with a petaland seed-like structure may induce neutron coherent scattering. We have studied a possible effect according to which the increase of the number of graphene seed-like structures produces an enhancement of the coherent scattering. To evaluate this, we focused on Raman spectra that characterize the stacking structure, crystal irregularities, and defects promoted by graphene growth. By focusing on this information, we tried to find parameters related to the nano-sized structure of graphene, and explored whether they can be related to the coherent scattering. As a result, it is suggested that the increase of the G/D ratio and the decrease of the G/2D ratio in the Raman spectra correlate strongly with the increase of the coherent scattering.

Enhancing the resonance stability of microelectromechanical systems (MEMS) resonator is critically important for achieving high-resolution performance in advanced sensing applications. Higher-order mode resonance yields a greater product of resonance frequency and quality factor, thereby enabling high-speed sensing. In this work, we show that higher-order-modes actuation enhances the frequency stability of single-crystal diamond MEMS cantilever resonator. This approach offers a promising strategy to develop highly precise MEMS sensors.

Diamond, with its ultra-wide bandgap energy, has emerged as an extreme semiconductor due to its extraordinary electronic and thermal properties. The hydrogen-terminated diamond surface has attracted extensive attention due to its unique p-type surface conductivity. However, the fundamental nature of this p-type conductivity remains incompletely understood using existing surface analysis techniques. In this study, we investigate the dynamic thermal desorption of surface adsorbates on hydrogen-terminated diamond using single-crystal diamond microelectromechanical systems resonators, avoiding charging-related issues. By analyzing variations in resonance performance and surface conductivity, we uncover several key findings: (i) The desorption of surface adsorbates reaches saturation at approximately 873 K. (ii) The desorbed mass per unit area is around 2.3 fg/μm2, corresponding to an equivalent thickness of approximately 1 nm. (iii) The surface conductivity of hydrogen-terminated diamond can be fully restored even after annealing at 873 K, indicating the thermal stability of C–H bonds. This work offers an alternative insight into the surface properties of hydrogen-terminated diamond, accelerating the development of highly reliable diamond-based electronic devices.

To elucidate the complexity of cross-linking in multinetwork elastomers (MNEs), we employed small-angle neutron scattering combined with dynamic nuclear polarization (DNP-SANS). MNEs were designed as thermoplastic elastomers with three kinds of cross-linking consisting of hydrogen, covalent, and clay plane bonds. DNP-SANS profiles were obtained with continuously changing scattering contrasts for MNEs with different cross-link densities. We clearly recognize the three matching points in scattering intensity, originating from pairs of cross-linking groups, clay, or main chains. DNP-SANS profiles were decomposed into three partial scattering functions for self-terms of cross-linking groups clay and their cross-terms. The self-term exhibits a scattering maximum due to the interplane distance of clay, which changes with the cross-link density. The cross-term between clay and cross-link was obtained as negative, indicating that the cross-linking domains are tightly correlated, localizing on the clay surface. The results indicate that DNP-SANS is a crucial technique for obtaining structural details of MNE cross-linking without chemical deuteration.

We report the latest advances of the iMATERIA instrument, namely, time-of-flight small-angle neutron scattering (SANS) specifically for measurements in the manufacturing and energy industries. Observations are available that are multi-scale (from a minimum q min = 0.007 Å-1 to a maximum q = 30 Å-1), multi-time domain (>0.5 s) and multi-contrast by dynamical nuclear polarization. Multi-angle (or stereo) observation of film specimens can bridge between conventional SANS and reflectivity measurements. For multi-analysis, we have developed real-time simultaneous SANS and neutron radiography (NR), targeting polymer electrolyte fuel cells. In the future, we plan to establish simultaneous triple-analysis combining SANS, NR and prompt γ-ray analysis. By scanning with a beam of 1 mm2 in size, such analysis enables the mapping of structural parameters determined by SANS and elemental composition determined by prompt γ-ray analysis on the image obtained by NR.

Surface states of O-terminated diamond determine the electronic properties of devices. The in-situ realization of the surface properties in atomic scale relies on ultra-high vacuum and sophisticated techniques. Here, we propose the utilization of diamond microelectromechanical system (MEMS) to reveal the surface adsorption/desorption of oxygen (O)-terminated diamond. Our strategy is to measure the resonance frequency shift of diamond cantilevers by in-situ heating and cooling the cantilevers. Based on the frequency shift, the mass and thickness of the adsorption layer of O-terminated diamond was disclosed to be 0.0015 pg/mu m(2) and similar to 0.4 nm, providing a new insight into semiconductor electronics.

The precise characterization of bulk properties of thin homoepitaxial diamond layers with micrometer thickness is difficult due to the interference from the substrate. In this work, we utilized smart-cut method to fabricate single-crystal diamond (SCD) cantilevers or plates and transferred them to a foreign substrate (SiO2/Si). The mechanical resonance of the SCD cantilevers was characterized to confirm that the ion-implantation-induced damaged layer was nearly removed under the cantilever. Raman, photoluminescence (PL), and cathodoluminescence (CL) measurements were conducted on the transferred SCD cantilevers/plates and homoepitaxial layers on the substrate with and without ion implantation. As a result, it was found that both of the Raman spectral properties of the SCD layer on the ion-implanted regions and the freestanding SCD plates/cantilevers successfully avoid interference from the substrate. PL analysis showed no emission peaks attributable to nitrogen and other defects from the epilayers. Additionally, CL analysis from the freestanding cantilevers/plates disclosed the exciton emission at around 236 nm at room temperature. These results suggest the high crystal quality of the SCD cantilevers for MEMS applications.

To enhance the intensity of neutron beams, attention has been focused on the coherent scattering caused by nano-sized particle ensembles, and the use of nano-diamonds has been actively considered. Graphene, which has an sp2 carbon crystal structure, has a larger van der Waals force compared to sp3 carbon crystal structure such as nano-diamonds. Additionally, the bonding force between carbon atoms in graphene is strong, which makes it easier to mold into a large block and plate and to adapt to higher radiation fields. However, graphene is easily to cause aggregation due to its large van der Waals force, making it difficult to form a nano-sized three-dimensional structure. To address this problem, we focused on the hot isostatic pressing (HIP) method, which uses resin powder as the raw material and produces vapor-phase-grown graphene through HIP treatment. We have reported a method for producing free-standing, three-dimensional graphene called "graphene flower" made of nanosized graphene and a method for controlling the nano-size of graphene. Additionally, we presented a prototype of a graphene neutron reflector and measured the coherent scattering of neutrons by graphene for the first time. In this paper, we will report on the optimization of the graphene manufacturing method using the HIP process to improve the coherent scattering performance of neutrons.

The exceptional stiffness of diamond is strongly anisotropic due to its crystal structure, yet experimental quantification of Young's modulus along different orientations remains limited. Here, we present a direct measurement of elastic anisotropy in microwave plasma chemical vapor deposition (MPCVD) single-crystal diamond (SCD) by analyzing the resonance frequencies of cantilevers aligned along distinct crystallographic directions. The measured Young's modulus exhibited a minimum value of 1085 +/- 21 GPa along the < 100 > direction and a maximum value of 1189 +/- 22 GPa along the < 110 > direction. The compliance constants derived from the MPCVD-SCD differ substantially from previously reported values for natural diamonds and are more consistent with first-principles theoretical values. This method enables precise determination of orientation-dependent stiffness, revealing significant variation in Young's modulus across crystallographic axes. These insights are critical for the design of diamond-based micro- and nano-mechanical systems as well as other high-precision devices, where directional elasticity strongly influences performance.

Single-crystal diamond (SCD) microelectromechanical systems (MEMS) resonators with lower energy dissipation and higher quality (Q) factors have always been pursued for the development of high-sensitivity and high signal-to-noise ratio (SNR) MEMS sensors. The intrinsic loss such as the crystal quality and extrinsic loss of clamping loss have been examined to improve the Q factors of SCD MEMS resonators. Nevertheless, the surface termination induced energy dissipation has rarely been known due to the lack of high crystal quality diamond resonators and in-situ characterization. Here we examine the effect of oxygen-termination on the surface energy dissipation of SCD cantilevers by in-situ heating these cantilevers in a high vacuum chamber. After thermal treatment of the cantilevers at 933 K, the Q factor of the cantilever is improved from 2.8x105 to 3.3x105 (i.e. the 120 μm-long). The resonance frequency increase confirms the desorption of surface adsorbates. Compared to silicon, on which a native solid-state oxide exists, the surface oxygen-termination induced loss in diamond MEMS is much smaller. The non-existence of native oxides on diamond surface is an obvious merit toward ultra-high Q factor MEMS resonators.

Cs3PW12O40 (Cs3WPA) composites with CsHSO4 (CHS) were prepared, and their effects on proton conductivity were investigated. These composites comprise CHS, H2SO4, and Cs3WPA, where the Cs3WPA served as the matrix element. The CHS in the composites became amorphous, and it was caused by the strong acidic catalytic properties and a large surface area of Cs3WPA. Amorphous-CHS provides an effective proton carrier, and the conductivity increases with increasing amorphous-CHS content. CHS-H2SO4-Cs3WPA ternary system was prepared based on the three aforementioned components of the composites. It was found that the activation energy of proton conductivity for the ternary system is lower than that of a composite with an identical composition. The difference of activation energy between composite and ternary system results from the difference of the quantity of incorporated water molecules.

MEMS resonant sensing devices require both HF ( f ) and low dissipation or high quality factor ( Q ) to ensure high sensitivity and high speed. In this study, we investigate the resonance properties and energy loss in the first three resonance modes, resulting in a significant increase in f‧Q product at higher orders. The third order resonance exhibits an approximately 15-fold increase in f‧Q product, while the Q factor remains nearly constant. Consequently, we achieved an ultrahigh f‧Q product exceeding 10 12 Hz by higher-order resonances in single-crystal diamond cantilevers.

Nearly all sensors inevitably suffer from environmental influence such as temperature fluctuation. To precisely process the external signals, independent temperature compensation devices or electronic circuits are usually required, making the overall system and algorithms sophisticated. Especially, when the environment temperature is as high as over 200 degrees C, both the sensors and temperature-compensation devices encounter the reliability problem. In this work, an intelligent multifunctional sensor utilizing single-crystal diamond (SCD) microelectromechanical (MEMS) resonators is demonstrated that can sense both magnetic fields and temperatures up to 300 degrees C, independently. The strategy is to integrate a magnetostrictive thin film and a non-magnetic thin film on different diamond MEMS resonators on the same diamond chip for simultaneous magnetic field sensing and temperature monitoring, respectively. The multi-resonators based on diamond MEMS offer a promising platform for multi-parameter sensing immune to environment interference. Through integrating a magnetostrictive thin film and a non-magnetic thin film on different diamond MEMS resonators on the same diamond chip, an intelligent multifunctional sensor utilizing SCD MEMS that can sense both magnetic fields and temperatures is developed. Diamond MEMS highlights its potential for future multi-sensing applications of high integration, multifunctionality, and miniaturization. image