Two-dimensional materials such as monolayer transition metal dichalcogenides, and their van der Waals heterostructures have attracted tremendous attention because of intriguing electronic and optical properties related to extreme low-dimensionality. The moiré structure in twisted van der Waals heterostructure drastically endows novel optical properties and functionality originating from twist angle-dependent electronic properties. In this article, we introduce the novel optical physics arising from moiré exciton in a twisted WSe₂/MoSe₂ heterobilayer, offering applications for quantum information and quantum optics.

Synchrotron radiation facilities, which are compared to giant microscopes, are used for cutting-edge researches in various fields because the characteristics of the emitted X-rays enable observation with extremely-high resolution that cannot be achieved with laboratory scale analytical equipment. High-precision optical elements are indispensable to obtain this high resolution, and the authors are the only company that provides a stable supply of X-ray total-reflection mirrors with surfaces smoothed to a remarkable accuracy of less than 2 nanometer. This paper describes existence of unique nanofabrication technology behind this global niche top business, its successful practical application and commercialization, and introduces an example of an application development of a new technology.

Low-dimensional materials are expected to be new materials for next-generation devices, but their mass synthesis and implementation to large volume or large area devices are one of the major challenges. In this paper, the fabrication of nanosheet bundles of silicon, silicide and related materials using layered crystals such as CaSi₂ as templates is shown.

　Powdered bundles consisting of nanosheets with a thickness of several nanometers to several tens of nanometers were obtained, and the Si and silicide nanosheet bundles were also prepared in the form of microwalls on Si substrates. This paper introduces the progress from nanosheet bundle synthesis by solid-vapor phase reaction to nanosheet bundle synthesis in aqueous solutions, metal melts, and molten salts.

Mobile applications such as electric vehicles are being considered a novel market for photovoltaic power generation. These applications need much power generation with a confined installation area. Therefore, highly efficient multi-junction solar cells composed of III-V semiconductors are expected to use. However, the high manufacturing cost hinders its widespread use, and the current applications are limited. This paper introduces low-cost crystal growth, epitaxial-lift off, and bonding technology to reduce the cost of III-V multi-junction solar cells.

There are numerous amounts of nanoparticles in the universe, and they play an important role in various situations. Nevertheless, their formation processes have been unknown. We have been conducting experiments to elucidate the nucleation processes from the gas phase, believing that the key to understanding the material evolution in the universe lies in the characteristic properties in nanoscale. As a result, we found that the key factors for homogeneous nucleation from the gas phase are dimer formation and decreasing of melting point. In addition, particle mediated growth plays an important role in dust formation. Here, we introduce some of our resent results.

We present the basic concept, theoretical conversion efficiency, and experimental results of the high-efficiency solar cells, the two-step photon up-conversion solar cells, which we have proposed. The experimental results show that the insertion of the quantum dots layer beneath the semiconductor hetero-interface improves the efficiency of intraband transition (photon up-conversion) occurring at the hetero-interface. Finally, current efforts to realize low-cost, high-efficiency two-step up-conversion solar cells are presented.

In this short review, I explain the basics of pulsed field generation techniques and introduce the practical situation of high magnetic field researches. First, a conventional way for generating a pulsed magnetic field (short pulse) is presented, and the difference between this and so-called long-pulse magnetic field which is representative of an easy-to-use pulse magnetic field is discussed. Next, the flat-top field generated by the state-of-the-art feedback technique is described and its usefulness is discussed. Finally, recent high-field research trends made possible by these field generation techniques are presented.