As semiconductor devices continue to scale down, conventional inspection techniques such as scanning electron microscopy (SEM) face challenges in visualizing chemical state distribution in next-generation devices such as complementary field-effect transistors (CFETs) with two-dimensional material channels. This study explores the application of laser-based photoemission electron microscopy (Laser-PEEM) as an alternative semiconductor inspection method. Laser-PEEM enables high-throughput, non-destructive imaging with chemical sensitivity and deep detection capabilities. We demonstrate its effectiveness through two case studies : (i) the observation of dielectric breakdown in ferroelectric capacitors, where Laser-PEEM successfully visualized defect formation before catastrophic failure, and (ii) latent image detection in electron beam resist, where Laser-PEEM achieved significantly higher throughput than atomic force microscopy (AFM) and SEM. These findings indicate that Laser-PEEM has the potential to improve semiconductor defect detection, leading to improved yield and process efficiency in advanced manufacturing.

Doping materials and forming thin films are essential techniques in modern science and technology. However, observing the three-dimensional atomic structures of dopants and thin film interfaces has been difficult using conventional technics. Recently, atomic-resolution holography has been developed as a powerful technique for directly visualizing such three-dimensional local atomic arrangements. Among various types, photoelectron holography is particularly advantageous due to its high surface sensitivity. its ability to detect light elements, and its capability for atomic site identification. This paper introduces the principles and applications of photoelectron holography.

This study presents a real-time atomic-resolution observation of chemical reaction dynamics at the single-molecule level using single-molecule atomic-resolution time-resolved electron microscopy (SMART-EM). [60]Fullerene (C₆₀) molecules were encapsulated in carbon nanotubes and monitored at 1600 frames per second using a direct electron detection (DED) camera. To overcome the inherently low signal-to-noise ratio in such ultrafast imaging, we applied Chambolle total variation denoising, enabling clear visualization of single-frame structures. This allowed us to resolve a cascade reaction featuring multiple transient intermediates, including a highly strained, short-lived species (＜3 ms). Structural identification was achieved via cross-correlation image matching analysis with simulated TEM images based on Osawa-Tomanek models. Even fleeting high-energy states were experimentally captured, validating theoretical predictions and revealing the stochastic nature of molecular trajectories. This work establishes a new paradigm for visualizing molecular dynamics, highlighting the emerging field of “cinematic chemistry.”

Since the invention of scanning tunnelling microscopy and atomic force microscopy, the manipulation of single atoms and molecules has attracted tremendous interests of researchers. Particularly, combining with bond-resolved scanning probe microscopy, this field has been rapidly developed. In this contribution, I will present current topics from our group, including on-surface syntheses of three-dimensional and heteroatom substituted nanocarbon materials. The unique structure of these compounds enabled systematic tip-induced chemical reactions, syntheses of the highly reactive diradical products. Their electronic and magnetic properties were analyzed using low-temperature scanning tunneling microscopy. Additionally, we synthesized the spin-1/2 Heisenberg molecular chain and characterized their magnetic couplings.

Hydrogen readily permeates various materials and modulates their physical properties. Identification of the hydrogen lattice location in crystals is key to understanding and controlling the hydrogen-induced phenomena. Combining nuclear reaction analysis (NRA) with the ion channeling technique, we experimentally determined the locations of H and D in epitaxial nanofilms of titanium hydrides. We found that 11 at.% of H are located at the octahedral site with the remaining H atoms in the tetrahedral site. Density functional theory calculations revealed that the partial octahedral site occupation is attributed to the Jahn-Teller effect induced by hydrogen. In contrast, D was found to solely occupy the tetrahedral site owing to the mass effect on the zero-point vibrational energy. This study demonstrates the potential to fabricate hydrides with arbitrary site occupancy by tuning the isotope ratio, which potentially allows for control over their electronic properties and leads to the discovery of novel phenomena.