Crystalline low-dimensional materials made of covalently bonded carbon atoms possess a diverse range of unique properties that are promising for various applications. Their properties can greatly vary, depending on their atomic arrangements, sizes, and dimensionality. In particular, the optical, mechanical, and thermal properties of carbon nanotubes and graphene have attracted considerable attention from both fundamental and applied viewpoints. From a physics point of view, carbon nanotubes and graphene, respectively, provide one- and two-dimensional platforms with characteristic spatial scales of only 1 nm for fundamental studies of quantum phenomena. Recent years have seen remarkable advances and innovations in the preparation of different types of large-scale architectures and devices of ordered and purified carbon nanomaterials. These developments are currently revolutionizing the field of optical science of carbon nanotubes and graphene toward real-world applications of carbon-based optoelectronic devices. In this article, we provide an overview on the frontier of this rapidly progressing research field.

We describe the principles and applications of two essential methods for measurement of electron temperature and the density of non-equilibrium plasmas including atmospheric-pressure discharge, based on optical emission spectroscopic (OES) measurement, i.e., line intensity measurement assisted with a collisional radiative model, and continuum spectrum measurement as electron-neutral bremsstrahlung. For the former scheme, we introduce three practical procedures to interpret the OES results based on the excitation kinetic model, which are the “selection of the dominant elementary processes”, the “measurement of two pairs of line intensities”, and the “conversion of the excitation temperature to the electron temperature”. In the last part, examples are shown for the demonstration of the continuum measurement, which has the potential to deduce the electron energy distribution function, followed by its future prospects.

The spatial resolution of aberration-corrected scanning transmission electron microscopy (STEM) has now become better than 0.5 Å. Combining such an ultrahigh resolution STEM with a differential phase contrast (DPC) imaging technique, we can now directly visualize the electric field distribution inside individual atoms in real space. This atomic electric field, i.e. the field between the nucleus of the atom and the electron cloud that surrounds it, should contain information about the atomic species and the charge redistribution due to chemical bonding. In this report, the current status of atomic-resolution DPC STEM and its future direction are discussed.

We have developed new process technologies for small process spaces in Minimal Fab for low-volume device production. In this work, we summarize useful processes in Minimal Fab that have not been employed in conventional fabs. For example, a small wafer has a strong surface tension at the wafer edge that keeps a volume of liquid on it, which has led us to the development of a spin droplet cleaning process. Beam-type technologies scan over a small wafer area with a short beam scanning time letting us develop a maskless UV exposure system, with a nozzle micro-plasma while laser heating without scanning is uniformly applied over the wafer. In plasma etching, the plasma size is much smaller than the chamber size and is isolated far from the chamber wall, therefore the process is less contaminated. Moreover, the small chamber lets us realize high-speed etching with a cycle time of 2 seconds in an alternative gas feeding and time-multiplexing process. In the transistor manufacturing processes, using our developed clean-localized wafer transfer system, we have found that the density of the interface states of MOS capacitors is related to the relative humidity in the atmosphere.

Sophisticated functions and algorithms of living creatures potentially provide us with knowledge useful for future innovative technologies. Bats and dolphins have evolved echolocation capabilities, which are called biosonar. Now sensing needs are advancing with examples such as automatic driving technology. It is important to learn from a biosonar system that has advanced skills using a simple mechanism. By utilizing various measuring techniques, the unique echolocation behavior of bats has gradually come to light. In this article, we introduce an outline of the biosonar system of bats and our recent research results about the effective foraging strategy of wild bats, and jamming avoidance behavior during group flight with conspecifics.

Vector beams are the light beams whose polarization distributions are not spatially uniform. Based on this, many new properties including small spot formation beyond the diffraction limit have been discovered. The generation methods and their application to a super-resolution microscope using vector beams are introduced.