As a post-OLED (organic light emitting diode) device, expectations are rising for an organic semiconductor laser diode (OSLD), which is the ultimate current injection device. In order to realize OSLD, the achievement of high current density of several kA cm^－2 and the development of laser molecules exhibiting ultra-low threshold has been required. This paper introduces the recent progress in molecular design for laser molecules aimed for OSLDs.

Plasma catalysis is gathering attentions for its unique characters in chemical reactivity and product selectivity. Various applications have been suggested and demonstrated. When catalysts are located inside the plasma zone, bilateral interactions occur which are generally complicated to get full understanding of the detailed steps. Nevertheless, a lot of experimental results have been filed up for various chemical reactions (decomposition, synthesis, partial redox). Notwithstanding the progress during the last decades, however, the understanding of the working mechanism is still in early stage. As a representative model reaction, room temperature oxidation of CO was compared for the conventional thermal catalysis, plasma-driven catalysis, and ozone-assisted catalysis. The effect of different catalyst, reaction mechanism, and catalyst regeneration was discussed. In this review, the current progress to understand the bilateral interactions of plasma and catalyst, literature survey, and some of future perspective will be presented.

Progress of novel fabrications for functional surfaces using various shapes and materials are introduced such as subwavelength optics, biomimetic, electric devices, related to capability of advanced nanoimprint technology

We demonstrate the cold emission of ytterbium atomic vapors from ytterbium oxide irradiated with a simple ultraviolet diode laser. Slow atoms are trapped by a magneto-optical trap using a dipole-allowed strong transition at 399 nm. Accompanying phenomenon of the emission of white light from the irradiated ytterbium oxide sample is preliminary investigated. This method will open the way towards a compact and transportable optical lattice clock.

In this review, we summarize recent progress achieved in on-surface bottom-up growth of graphene nanoribbons (GNRs) with well-defined edges. First, we show the simulation results suggesting that a GNR backward diode with GNR heterojunction can outperform the state-of-the-art diodes owing to their negligible junction capacitance. The major challenge required for achieving high-performance GNR diodes is low contact resistance and well-defined GNR heterojunction. The second part of this review is dedicated to our recent works on GNR heterojunctions by modifying electronic states by edge-functionalization. It was revealed that the important design policies for precursors are as follows : molecular design avoiding intramolecular steric hinderance upon polymerization, precursor design considering dehydrogenation path, and precursor design considering intramolecular side reaction. We also demonstrate our preliminary results of GNR-FET, which suggest that wider GNRs with narrower band gap is required for the electronic devices.

We have developed scanning tunneling potentiometry (STP) operating in ultrahigh vacuum conditions, which provides us a surface topography and the corresponding electrochemical potential distribution simultaneously in nanometer scale special resolution and µV-level potential sensitivity under a lateral electrical current flowing parallel to the sample surface. Using this setup, we have successfully performed an STP measurement on the Si(111)-7×7 reconstructed surface, which holds metallic surface states. Our observation indicates that not only steps but also phase boundaries of the Si(111)-7×7 surface work as an electrical resistance impeding the conductance through the surface states. From the evaluation of the ratio of conductivity across the one-dimensional line defects to that of the terrace on the Si(111)-7×7 surface, the conductivity of the phase boundary is found five times that of the monolayer-height step.

Three types of semi-empirical equation for calculating the gas flow rate in a cylindrical tube of arbitrary length-to-diameter ratio are proposed. The solutions of these equations cover all flow regimes from molecular flow to critical flow or subcritical flow via intermediate flow, viscous laminar flow, and turbulent flow. In addition, the calculation procedure is straightforward because it does not require selecting a suitable equation based on the Knudsen number, Reynolds number, and Mach number. Comparing the solutions of the proposed equations with reported results from experiments and computer simulations shows good agreement within 30%.

Microscopic studies on electrolyte solution / electrode interfaces provide the most fundamental information not only for understanding the electric double layer formed at the interfaces but also for designing sophisticated electrochemical (EC) devices. In this study, we developed tip-enhanced Raman spectroscopy (TERS), which is based on an electrochemical scanning tunneling microscope (EC-STM), and demonstrated electrochemical TERS (EC-TERS) measurements of benzenethiol monolayers on Au(111). A specially-designed cell enables us to carry out reproducible EC, EC-STM, and EC-TERS measurements, which indicates consistent results among these techniques for the oxidative desorption of the benzenethiol monolayers.

Electret or permanent electrical charge is used as a part of mechano-electric energy conversion system for vibrational energy harvesting device. Microscopic capacitors are produced by silicon micromachining or MEMS (microelectromechanical systems) fabrication process, and the surfaces are turned into impurity-rich silicon oxide, which is later processed to make an electret by displacing the impurity ions by the same mechanism as the anodic bonding. The built-in potential of the electret is used to produce electrical current through the electrostatic induction when the movable electrode is periodically shaken by the external vibrations. In this article, the fabrication processes for the electret as well as the MEMS vibrational energy harvester are discussed. The fundamental characteristics of the energy harvesters are reported, along with a demonstration result as an autonomous powerpack for an IoT (internet-of-things) type wireless sensor node.

Soil is defined as a mixture of weathering products of rocks (sand, silt, and clay) and humus (or soil organic matter) derived from plant or animal. World soils are divided into 12 groups and their distribution is not uniform. Soil degradation includes soil acidification in humid region, salinization in arid regions, and loss of soil organic matter in both regions. Minimum tillage or optimized fallow systems can minimize loss of soil organic matter and improve soil fertility. Understanding of complex soil system is required for food supply and human survival.

Digital Annealer developed by Fujitsu is a new architecture to solve “combinatorial optimization problems” at high speed with digital circuit inspired by quantum phenomena. The features are stable operation with digital circuit at room temperature, easy miniaturization, and easy mapping more complex problems with a fully-connected architecture. The Digital Annealer is easy to apply actual problems and contributes to customers in a wide range of businesses, including drug discovery, chemistry, manufacturing, transportation, finance, and logistics. In this article, we explain the fundamental of the Digital Annealer including the speedup technique. We also introduce an application to the material development using the Digital Annealer. The Digital Annealer is used to evaluate the structural similarity of the flavor molecules. We found that the molecules with high structural similarity show a similar flavor. We also extracted the common substructure of molecules having the similar flavor, which is considered to be the key structure of the flavor.

The fundamentals for understanding metal corrosion in aqueous solutions are first explained in terms of thermodynamics and kinetics of electrochemical corrosion reactions, illustrating the validity of a local cell model for the uniform corrosion behavior of iron and stainless steels. Then, the passivation process of stainless steels and the important properties of their passive films are described. Finally, recent studies on the pit initiation mechanism at sulfide inclusions of stainless steels are introduced, which provides a valuable information to develop a next-generation green stainless steel.

Recent progress of the microfabricated field emitter array (FEA) and the planar type electron source is overviewed. The volcano-structured double-gate FEA is promising for obtaining matrix driven and focused electron beams. The beam half angle less than one degree was achieved by using this structure. High current density of more than 25 A/cm² is also achieved by using nickel-based alloy as an emitter material. A major breakthrough in the field of planar type electron sources is a using graphene as a top electrode in Metal/Oxide/Semiconductor type emitter, which is owing to the development of the direct deposition technique of graphene on insulating material. The emission efficiency of more than 30% is achieved. The graphene/oxide/semiconductor type electron source can emit electrons not only in poor vacuum but also in liquid. This unique feature enables new application, such as hydrogen production using non-electrolyte aqueous solution by injecting low energy electrons.

Based on the “Sustainable Zoom-Zoom” plan, Mazda's long-term vision for technology development, we have been advancing what is called a “Building Block Strategy”.

With use of a new-generation technology called “SKYACTIV TECHNOLOGY”, we intend to thoroughly improve Mazda's base technologies with an eye to improving the powertrain efficiency, reducing the vehicle weight, and eventually combining them with electric device technologies in a phased manner so as to reduce total CO₂ emissions.

As the second step of this approach, Mazda has developed a new regenerative braking system called “i-ELOOP”, where the energy generated during deceleration is recovered and reused as electric energy necessary for a vehicle to move.

This paper introduces the Electric Double Layer Capacitor (hereinafter referred to as EDLC) and as device technologies of the “i-ELOOP”, a regenerative braking technology developed as the second step of the Building Block Strategy.

In recent years, imaging quality of a CMOS image sensor (CIS) is remarkably improving. This paper reviews the technology development of CIS for mobile devices.

Conventional semiconductor heterojunctions with two-dimensional (2D) interfaces have been an important topic, both in solid state physics and in electronics and optoelectronics applications. Recently, the in-plane heterostructures based on 2D materials are expected to provide a novel one-dimensional (1D) interface with unique physical properties and applications. Even though there have been many reports on the growth studies of such heterostructures, it is still an important challenge to develop a sophisticated growth process of novel heterostructures/superlattices and high-quality samples without interface degradation, contamination and/or alloying. In this article, the author introduces our recent progresses of thermal chemical vapor deposition (CVD) growth of 2D materials including graphene, hexagonal boron nitride, and transition metal dichalcogenide (TMDC), and their heterostructures.

X-ray photoelectron spectroscopy (XPS), which is capable of analyzing the elemental composition and the oxidation states of surfaces and interfaces placed in a vacuum, was applied to observe ionic species dissolved in aqueous solutions. An environmental cell using a 5-nm thick silicon nitride membrane as a quasi-transparent window for incident x-rays and emitted photoelectrons was developed, and cesium chloride aqueous solutions with a variety of concentrations enclosed in the cells were measured using a laboratory-based XPS apparatus equipped with an Al-Kα source. Cs 4d photoelectrons emitted from cesium ions in the solutions were detected passing through the membrane. Moreover, the peak intensity increased proportionally with the concentration of cesium chloride, proving that this technique allows us to conduct quantitative analysis of solution species.

We fabricated metastable palladium hydride by hydrogen ion implantation to a 10 nm-thick Pd film at 7 K, and monitored the hydride formation and relaxation to a stable state by resistivity measurements. By heating the sample, we observed a substantial change in resistivity below 100 K without accompanying hydrogen desorption. While the resistivity change was observed at 80 K for both H and D, it was observed only for H at 6 K. This irreversible resistivity change is attributed to transition from the metastable state to its stable state by hydrogen diffusion. It is considered that hydrogen atoms undergo diffusion thermally at 80 K and by quantum tunneling at 6 K.

We have established the original methodology that enable to observe atomic orderings and arrangements of “surfaces with arbitrary directions” on 3D figured structures, by developing diffraction and microscopy techniques. An original technique, namely, the directly and quantitatively viewing of the side- and facet-surfaces in atomic scale using reflection high-energy electron diffraction (RHEED) and scanning tunneling microscope (STM), can feedback to the determination of process parameters in the etching procedure. The scientifically optimized etching recipe enabled the creation of atomically-ordered side-surfaces, which are perpendicular to planar substrate surfaces on 3D patterned Si substrates. RHEED and STM prove atomically-reconstructed Si{100}2×1, {110}16×2, and {111}7×7 side-surfaces that were realized for the first time. We have also developed the atomically-ordered 3D nanofabrication technique, where the material stacking direction is switched from the general out-of-plane to in-plane direction, and realized the formation ultra-thin epitaxial films in 3D space.

SuperKEKB is an electron–positron collider with asymmetric energies at KEK aiming at a high luminosity of 8.0×10³⁵ cm^－2 s^－1. During the Phase-1 commissioning from February to June 2016 and the Phase-2 commissioning from March to July 2018, the vacuum system worked well as a whole, and the increase in pressure per unit beam current decreased steadily. The photodesorption coefficients at arc sections reached approximately 1×10^－6 molecules photon^－1 and 7×10^－8 molecules photon^－1 finally for the positron and electron rings, respectively. The beam lifetime was mainly limited by the Touschek effect in both rings, rather than the beam-gas scattering. The electron cloud effect was observed in the positron ring during Phase-1, but it was suppressed by additional countermeasures applied before Phase-2.