Article
Engineering, Electrical & Electronic
R. A. Izmailov, B. J. O'Sullivan, M. I. Popovici, V. V. Afanas'ev
Summary: Electron traps in ferroelectric HfO2 and HfZrO4 were studied using charge injection and photodepopulation techniques. The concentration of occupied electron traps was found to be around 1019 cm-3 for all samples, and the energy distributions exhibited three characteristic optical energy levels.
SOLID-STATE ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
R. A. Izmailov, B. J. O'Sullivan, M. Popovici, V. V. Afanas'ev
Summary: The study investigates electron trapping in ferroelectric and non-ferroelectric HfO2-based layers at room temperature through charge injection and photodepopulation techniques. Comparisons of trapped electron energy distribution and density in differently processed samples show insignificant impact of Al and Si doping on trapping properties, suggesting the intrinsic nature of observed traps. The volume concentration of deep traps, mostly distributed energetically between 2 and 3.5 eV below the HfO2 conduction band, is found to be in the range of 1019 cm-3.
SOLID-STATE ELECTRONICS
(2021)
Article
Materials Science, Multidisciplinary
Kuan-Wun Lin, Jenn-Gwo Hwu
Summary: This study investigated the influence of local oxide thinning (LOT) spots on the electrostatics of MOS capacitors, finding that the introduction of LOT spots causing significant gate leakage leads to severe deep depletion (DD) above threshold, making the capacitors inapplicable for MOSFETs. The research also analyzed the effects of capacitor size, spot size, and spot thickness on the DD behavior, demonstrating the high impact of LOT spots on device operations and emphasizing the importance of controlling oxide structural defects.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Ya-Xun Lin, Der-Sheng Chao, Jenq-Horng Liang, Jheng-Yi Jiang, Chih-Fang Huang
Summary: In this study, the DDD effects of proton irradiation on 4H-SiC MOS capacitors were investigated. The depth profiles and damage distributions of protons were predicted using the SRIM code. The results showed that incident protons led to the accumulation of defects in SiC crystal and an increase in interface traps between SiO2 and SiC. The C-V curves exhibited a distinctive bump phenomenon in the weak inversion region, indicating the presence of bulk traps. Incident proton energy also played a crucial role in interface deterioration.
MICROELECTRONICS RELIABILITY
(2023)
Article
Computer Science, Information Systems
Mayank Chaturvedi, Sima Dimitrijev, Hamid Amini Moghadam, Daniel Haasmann, Peyush Pande, Utkarsh Jadli
Summary: The study characterized oxide traps existing in 4H-SiC MOS capacitors with fast response times using an integrated-charge method, identifying active defects reducing the channel-carrier mobility in 4H-SiC MOSFETs.
Article
Chemistry, Multidisciplinary
Soohyung Park, Haiyuan Wang, Thorsten Schultz, Dongguen Shin, Ruslan Ovsyannikov, Marios Zacharias, Dmitrii Maksimov, Matthias Meissner, Yuri Hasegawa, Takuma Yamaguchi, Satoshi Kera, Areej Aljarb, Mariam Hakami, Lain-Jong Li, Vincent Tung, Patrick Amsalem, Mariana Rossi, Norbert Koch
Summary: The study explores the electronic charge rearrangement principle in heterostructures and the impact of temperature on the amount of charge transfer. It is observed that the ground-state charge transfer increases by a factor of 3 when going from low temperature to room temperature in a specific heterostructure setup. Further electronic structure calculations and modeling identify electron-phonon coupling and electronic coupling as key factors determining the charge transfer quantity.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Physical
Shaofeng Dong, Zunkun Tan, Qiaoshan Chen, Guocheng Huang, Ling Wu, Jinhong Bi
Summary: In this study, cobalt quantum dots were integrated into ultra-narrow bandgap dioxin linked covalent organic frameworks to fabricate a promising photocatalyst for solar-to-fuel conversion under full visible light spectrum. The cobalt quantum dots played a crucial role in boosting the photocatalytic performance and improving the CO2 adsorption capacity.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Xiao-Long Zhang, Xiaozhi Su, Ya-Rong Zheng, Shao-Jin Hu, Lei Shi, Fei-Yue Gao, Peng-Peng Yang, Zhuang-Zhuang Niu, Zhi-Zheng Wu, Shuai Qin, Rui Wu, Yu Duan, Chao Gu, Xu-Sheng Zheng, Jun-Fa Zhu, Min-Rui Gao
Summary: This study presents experimental evidence of narrowing the interlayer gap of metallic cobalt diselenide to create a high-performance catalyst for the selective production of H2O2 in an acidic environment. By enhancing the interlayer coupling, a favorable surface electronic structure is achieved that promotes the energetics for H2O2 production. The strongly coupled CoSe2 catalyst shows excellent performance and long-term stability in the production of H2O2.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Rajesh Kumar, Ednan Joanni, Sumanta Sahoo, Jae-Jin Shim, Atsunori Matsuda, Wai Kian Tan, Rajesh K. Singh
Summary: This article provides a comprehensive overview of the fabrication and electrochemical performance of electrode materials for supercapacitors. It focuses on different-sized carbon nanomaterials and emerging fabrication technologies. The drawbacks of each electrode material, current technological challenges, and promising research directions are also discussed.
Article
Physics, Multidisciplinary
Yi-Dong Yuan, Dong-Yan Zhao, Yan-Rong Cao, Yu-Bo Wang, Jin Shao, Yan-Ning Chen, Wen-Long He, Jian Du, Min Wang, Ye-Ling Peng, Hong-Tao Zhang, Zhen Fu, Chen Ren, Fang Liu, Long-Tao Zhang, Yang Zhao, Ling Lv, Yi-Qiang Zhao, Xue-Feng Zheng, Zhi-Mei Zhou, Yong Wan, Xiao-Hua Ma
Summary: Research has shown that the performance degradation of gate-recessed MOS-HEMT under channel hot electron injection stress is more severe than that of conventional HEMT, mainly due to the combined effect of traps in the barrier layer and gate dielectric; the threshold voltage of conventional HEMT decreases under gate electron injection stress, while the threshold voltage of gate-recessed MOS-HEMT first increases and then decreases as the conventional HEMT.
Article
Chemistry, Physical
Vilko Mandic, Stanislav Kurajica, Milivoj Plodinec, Ivana Panzic
Summary: This paper presents a strategy for the synthesis of high-performance p-type semiconductor nanoparticles. The materials were characterized using various techniques, including powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The photocatalytic activity of the synthesized materials was also evaluated.
Article
Chemistry, Multidisciplinary
Chih-Wei Wang, Xiaohan Liu, Tian Qiao, Mohit Khurana, Alexey V. Akimo, Dong Hee Son
Summary: This study identifies Mn-doped CsPbBr3 nanocrystals as an excellent platform for hot electron upconversion, benefiting from the structural diversity of metal halide perovskites. Two-dimensional Mn-doped CsPbBr3 nanoplatelets are particularly advantageous in the upconversion process due to the strong exciton-dopant interaction, and evidence for hot electron upconversion via long-lived dark excitons is observed.
Article
Chemistry, Physical
Qiu Zhang, Yuekun Zhang, Fengyan Li, Tingting Zhang, Lin Xu
Summary: The Cu2WS4/[Me2NH2]11[CeIII(PW11O39)2] (CWS/CeIII(PW11)2) composite was synthesized and used as a counter electrode material in CdS/CdSe/ZnS-sensitized quantum dot sensitized solar cell (QDSSCs). The CWS has more redox active sites than Cu2S due to the co-existence of copper and tungsten in different valence states. The CWS-4 CE showed the highest electrocatalytic activity and improved cell performance by generating shallow electron traps and inhibiting charge recombination.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
James Forsythe, Oleksandr Leiko, Vitalii Uvarov, Jan Skvara, Josef Myslivecek, Karel Masek, Viktor Johanek
Summary: Heteroepitaxial layers of ordered cobalt monoxide were prepared on single crystal Cu(111) substrate using two physical deposition methods. The structure and orientation of the CoO thin films were characterized, and the surface morphology was probed using scanning tunneling microscopy. It was found that only at low oxygen pressures could the cobalt monoxide phase be established on the Cu(111) surface.
SURFACES AND INTERFACES
(2022)
Article
Engineering, Chemical
Xiai Zhang, Wenquan Zhang, Jun Li, Tong Wang, Huanran Miao, Qikui Fan, Hao Zhu, Zhimao Yang, Chuncai Kong
Summary: In this study, a liquid-phase wet washing process based on PMS advanced oxidation was developed to effectively remove toluene. The CFQ/AC/PMS system achieved stable and efficient removal of toluene with high mineralization capability and reduced secondary air pollution.
SEPARATION AND PURIFICATION TECHNOLOGY
(2024)
Article
Electrochemistry
Yoshiaki Matsuo, Takuma Kino, Junichi Inamoto, Osamu Kimizuka, Motoaki Nishijima, Hajime Kinoshita
Article
Physics, Applied
Sungho Lee, Rui Liang, Yuki Miwa, Hisashi Kino, Takafumi Fukushima, Tetsu Tanaka
JAPANESE JOURNAL OF APPLIED PHYSICS
(2020)
Article
Energy & Fuels
Kakeru Fujiwara, Shogo Kayano, Masahiko Nishijima, Keisuke Kobayashi, Tetsuya Nanba, Taku Tsujimura
Summary: NiO and CeO2 catalysts prepared by flame spray pyrolysis exhibited high specific surface area and large pore volume, resulting in relatively small Ni particles during reduction. However, addition of Ni led to formation of uneven Ni particles after reduction. The former catalyst showed improved CO2 methanation performance compared to the latter catalyst, with higher CO2 conversion at 250 degrees C.
JOURNAL OF THE JAPAN PETROLEUM INSTITUTE
(2021)
Article
Chemistry, Physical
Yuki Ikeda, Masahiko Nishijima, Takanori Kiguchi, Toyohiko J. Konno
Summary: The crystal structure of martensite in Cu-27at.%Zn-9.0 at.%Al alloy was studied using HAADF-STEM and GPA, revealing changes in atomic rearrangements during martensitic transformation. The coherent interface between the phases with a slight tilt in the basal plane was also observed.
Article
Chemistry, Physical
Eri Miura-Fujiwara, Soichiro Yamada, Keisuke Mizushima, Masahiko Nishijima, Yoshimi Watanabe, Toshihiro Kasuga, Mitsuo Niinomi
Summary: Specific biomedical Ti and its alloys form a bright white oxide layer with high exfoliation resistance after oxidation treatment. The oxide layers on Ti-29Nb-13Ta-4.6Zr and Ti-36Nb-2Ta-3Zr-0.3O exhibit high exfoliation stress, suitable for artificial tooth coating, while CP Ti shows lower stress. The dense microstructures and composition-graded interfacial microstructure contribute to their high exfoliation resistance.
Article
Chemistry, Multidisciplinary
Hiroshi Naganuma, Masahiko Nishijima, Hayato Adachi, Mitsuharu Uemoto, Hikari Shinya, Shintaro Yasui, Hitoshi Morioka, Akihiko Hirata, Florian Godel, Marie-Blandine Martin, Bruno Dlubak, Pierre Seneor, Kenta Amemiya
Summary: A crystallographically heterogeneous interface was fabricated by growing hexagonal graphene (Gr) on a tetragonal FePd epitaxial film. The interface exhibited a short interatomic distance and an interface perpendicular magnetic anisotropy (IPMA) through chemisorption-type van der Waals force and enhanced orbital magnetic moment. This interface structure has potential applications in high-density magnetic random-access memory (MRAM).
Article
Engineering, Electrical & Electronic
Hiromichi Wakebe, Takafumi Fukushima, Tetsu Tanaka
Summary: This study demonstrates a fabrication technique of SU-8 microchannel suitable for microfluidic-based BLM formation and successfully forms BLMs, which is of great significance for drug targets and biosensing applications.
ELECTRONICS AND COMMUNICATIONS IN JAPAN
(2022)
Article
Chemistry, Physical
Tatsuya Joutsuka, Ryu Hamamura, Kakeru Fujiwara, Tetsuo Honma, Masahiko Nishijima, Shohei Tada
Summary: The combination of experiments and simulations revealed the structural and electronic origins of Cu-doped MgAl2O4 spinel-type oxides, which were developed as the catalyst precursor for CO2-to-methanol hydrogenation. The presence of elongated OeCu octahedrally coordinated [CuO6](el) in the spinel structure was confirmed at high doping levels. As the amount of doping decreased, [CuO6] el deformed to short O-Cu octahedrally coordinated [CuO6](s). Simultaneously, the surrounding O atoms became more negatively charged, and Cu nanoparticles with a size smaller than 10 nm were formed through H-2 reduction. The Cu nanoparticles derived from [CuO6](s) exhibited high selectivity for CO2-to-methanol hydrogenation.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Applied
Shohei Tada, Duanxing Li, Mina Okazaki, Hiroka Kinoshita, Masahiko Nishijima, Noriko Yamauchi, Yoshio Kobayashi, Kenta Iyoki
Summary: Highly efficient CO2 utilization methodologies combining methanol synthesis catalysts and methanol conversion catalysts have been developed. The use of ZnO/ZrO2 as the catalyst for methanol synthesis and MOR zeolites as the catalyst for methanol conversion enables one-pass hydrocarbon production via CO2 hydrogenation. By physically mixing these catalysts, bifunctional catalysts are formed, which operate at low pressure and have shown promising results in terms of olefin selectivity.
Article
Chemistry, Physical
Shohei Tada, Nagomu Ochiai, Hiroka Kinoshita, Mitsuhiro Yoshida, Natsumi Shimada, Tatsuya Joutsuka, Masahiko Nishijima, Tetsuo Honma, Noriko Yamauchi, Yoshio Kobayashi, Kenta Iyoki
Summary: This study investigated the effect of Zn content on the CO2-to-methanol hydrogenation over ZnxZr1-xO2-x catalysts and determined the active-site structure through calculations and experiments. The results showed that Zn species in the catalysts were unevenly distributed and formed clusters and nanoparticles near the surface. The Zn-O-Zr sites derived from the clusters exhibited specific activity for CO2 conversion.
Article
Geochemistry & Geophysics
Niccolo Satta, Masaaki Miyahara, Shin Ozawa, Hauke Marquardt, Masahiko Nishijima, Tomoko Arai, Eiji Ohtani
Summary: The observations on shock features recorded in a lunar rock sample returned by the Apollo 15 mission provide important insights into the behavior of rocks under high-pressure conditions. The presence of ferropericlase crystals confined in shock-melt pockets indicates the occurrence of shock-induced incongruent melting of olivine, a phenomenon never before observed in a natural sample. This incongruent melting can be used to estimate the pressure-temperature experienced by the sample during the impact event.
AMERICAN MINERALOGIST
(2022)
Article
Engineering, Electrical & Electronic
Yuki Miwa, Hisashi Kino, Takafumi Fukushima, Tetsu Tanaka
Summary: This study explores the use of transparent recording electrodes to enhance the performance of neural probes for optogenetics, using ZnO-based materials with good biocompatibility and transparency for potential application in biomedical devices.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2022)
Article
Chemistry, Applied
Kakeru Fujiwara, Taiki Akutsu, Masahiko Nishijima, Shohei Tada
Summary: In this study, ZnO-ZrO2 solid solution with high specific surface area was synthesized by flame spray pyrolysis under a lean-fuel condition. The dispersion state of Zn species in the particles and the presence of the Zrd(delta+) state were investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy. The catalytic activity of 28 at% ZnO-ZrO2 for CO2-to-methanol hydrogenation was found to be higher than that of 40 at% ZnO-ZrO2.
TOPICS IN CATALYSIS
(2023)
Article
Engineering, Chemical
Shohei Tada, Hiroka Kinoshita, Duanxing Li, Masahiko Nishijima, Harune Yamaguchi, Ryuji Kikcuhi, Noriko Yamauchi, Yoshio Kobayashi, Kenta Iyoki
Summary: In recent years, global warming caused by CO2 emissions has become a critical problem. In order to address this issue, a bifunctional catalyst that can convert CO2 to lower olefins in a single stage has been developed. The best performance of the catalyst was achieved when the two catalysts were mixed in close proximity.
ADVANCED POWDER TECHNOLOGY
(2023)
Article
Chemistry, Physical
Masaru Kondo, Tatsuya Joutsuka, Kakeru Fujiwara, Tetsuo Honma, Masahiko Nishijima, Shohei Tada
Summary: In this study, we investigated the Chan-Lam cross-coupling of imidazole and arylboronic acids using heterogeneous CuO/MOX catalysts under additive-free and mild conditions. Among them, CuO/t-ZrO2 showed the best performance, with a turnover number more than ten times higher than that of bulk CuO. Experimental and computational approaches revealed that the surface structure of CuO/t-ZrO2 contained abundant highly reducible Cu2+ species, specifically square-planar [CuO4], which played a crucial role in the coupling reaction.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)