Ulvac-Phi (Japan)

Metal-halide perovskites are promising light-emitter candidates for next-generation light-emitting diodes (LEDs)1-8. Achieving high brightness and efficiency simultaneously in pure-red perovskite LEDs (PeLEDs) is an ongoing goal9,10. Three-dimensional (3D) CsPbI3-xBrx emitters have excellent carrier transport capability and high colour purity, which could allow efficient and ultrabright pure-red PeLEDs. However, such devices are prone to efficiency roll-off, resulting in low efficiency and low brightness under high current density. Here, by using electrically excited transient absorption spectroscopy, we discovered the efficiency roll-off was induced by hole leakage. Therefore, we developed a CsPbI3-xBrx intragrain heterostructure containing narrow bandgap emitters and wide bandgap barriers to confine the injected carriers. The wide bandgap barrier was incorporated by introducing strongly bonding molecules into the [PbX6]4- framework to expand the 3D CsPbI3-xBrx lattice. This strategy resulted in bright and efficient pure-red PeLEDs, with a high brightness of 24,600 cd m-2, maximum external quantum efficiency of 24.2% and low efficiency roll-off, maintaining a 10.5% external quantum efficiency at a high luminance of 22,670 cd m-2.

Journal Article Surface Sensitive Chemical Imaging of Lithium Materials for Battery Applications by Auger Electron Spectroscopy Get access Ashley Maloney, Ashley Maloney Physical Electronics Inc., Chanhassen, Minnesota, United States Corresponding author: amaloney@phi.com Search for other works by this author on: Oxford Academic Google Scholar Masahiro Terashima, Masahiro Terashima ULVAC-PHI Inc, Chigasaki, Kanagawa, Japan Search for other works by this author on: Oxford Academic Google Scholar Kazutoshi Mamiya, Kazutoshi Mamiya ULVAC-PHI Inc, Chigasaki, Kanagawa, Japan Search for other works by this author on: Oxford Academic Google Scholar Shin-ichi Iida Shin-ichi Iida ULVAC-PHI Inc, Chigasaki, Kanagawa, Japan Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Page 771, https://doi.org/10.1093/micmic/ozad067.381 Published: 22 July 2023

Correction for ‘Single and dual metal atom catalysts for enhanced singlet oxygen generation and oxygen reduction reaction’ by Mohsen Tamtaji et al., J. Mater. Chem. A, 2023, https://doi.org/10.1039/D2TA08240C.

Focused ion beam (FIB) is commonly used as a standard machining technique in failure analysis, quality control, reverse engineering, material research, and so on, for the samples having microstructures and nanostructures. FIB combined with time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS), so‐called FIB‐TOF, has attracted attention as a method to determine the three‐dimensional (3D) chemical distributions of complex samples. In general, a highly focused Ga + ion beam is used for FIB, however, the FIB‐milled area is limited and it was difficult to expand the Ga‐FIB to hundreds of micron length scale for sample fabrication. In order to overcome the drawback, we proposed the Bi‐FIB approach for large scale sample cross‐sectioning. Although the possibility of Bi‐FIB has been reported, there were almost no performance examinations as well as practical applications. In this study, therefore, the authors summarize the comparison of milling rate and milling damage between Ga‐FIB and Bi‐FIB. As a result, it was found that Bi‐FIB can provide a higher milling rate with thinner milling damage. Finally, the Bi‐FIB approach was applied to the interfacial analysis of all‐solid‐state battery (ASSB) material. With this approach, the detailed chemical distributions at the interface were discovered, leading to the better understanding of battery behaviors.

A nearly-ideal edge termination for GaN p–n junctions was designed and demonstrated using Mg-ions implanted field limiting rings (FLRs). The FLRs were fabricated via the ultra-high-pressure annealing process after implanting Mg-ions into the etched n-type region outside the main p–n junction. The results of the technology computer-aided design simulation indicate that by optimizing the space and width of the rings, the breakdown voltage (BV) can be increased by over 90% of the ideal parallel plane BV (973 V). Accordingly, the fabricated diodes exhibited low leakage current and a BV of 897 V (92% of the ideal BV).

In recent years, all-solid-state batteries (ASSBs) have been attracting attention as the next generation batteries for electric vehicles, energy storage systems, etc. Despite the growing interest, there are still many challenges faced in the commercial use of ASSBs. One of the biggest issues is the internal resistance, especially generated at the interface between solid electrolyte and electrode. The internal resistance at the interface limits the charge-discharge cycling performances. In order to solve this issue, it is necessary to examine the chemical and physical interactions at the interface. In this study, we have performed a detailed characterization of a LiPON/LiCoO2 interface using time-of-flight secondary ion mass spectrometry, x-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and low-energy inverse photoelectron spectroscopy to obtain information on chemical species, chemical compositions, chemical states, and energy band diagrams. These powerful techniques have revealed that an interlayer between LiPON and LiCoO2 was formed due to the temperature rise during the manufacturing process. The temperature rise caused a change of the LiPON network structure and stimulated Co reduction in the LiCoO2 layer near the interface. Energy band diagram analysis suggests that the electron diffusion from LiPON to LiCoO2 may have triggered the reduction of Co. We concluded that the chemical changes that occur at the interface caused an increase in interfacial impedance. Preventing the chemical reduction of Co would be a key to minimize the internal resistance. In this article, the detailed chemical interactions between the LiPON and LiCoO2 layers will be discussed.

Isochronal annealing was performed on Mg-ion-implanted GaN under 1 GPa N2 ambient pressure for 5 min at temperatures of 1573–1753 K. Secondary ion mass spectrometry showed diffusion of Mg atoms and introduction of H atoms during annealing. Deeper diffusion was observed with increasing temperature. From Hall-effect measurements, p-type conductivity was found even for the sample with the lowest annealing temperature of 1573 K. For this sample, the acceptor activation ratio was 23% and the compensation ratio was 93%. The acceptor activation ratio increased to almost 100% and the compensation ratio decreased to 12% with increasing annealing temperature.

The biggest advantage of time-of-flight secondary ion mass spectrometry (TOF-SIMS) is imaging performance. TOF-SIMS is the only surface analysis technique which can provide the elemental and molecular ion images with high spatial resolution and high sensitivity. However, acquiring accurate images of uniform intensity from three-dimensional (3D) objects having curved surfaces is challenging because the ion extraction field in a TOF-SIMS system is ideally suited for the measurement of flat samples. When the authors observe the samples which have curved surfaces, the observable region is often restricted; it is, therefore, impossible to discuss the chemical abundance of components at various locations on the sample surface. Several methods to solve this problem have been proposed, e.g., delayed extraction or embedding the sample, but each has some disadvantages. Therefore, the authors have developed a curved surface sample holder for the uniform extraction of ions from 3D objects. This sample holder succeeded to expand the observable region dramatically without any significant drawbacks. In this article, the capability for uniform imaging afforded by the newly designed sample holder will be demonstrated.