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Revealing the microstructures of metal halide perovskite thin films via advancedtransmission electron microscopy
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作者 Yeming Xian Xiaoming Wang Yanfa Yan 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期30-41,共12页
Metal halide perovskites (MHPs) are excellent semiconductors that have led to breakthroughs in applications in thinfilmsolar cells, detectors, and light-emitting diodes due to their remarkable optoelectronic propertie... Metal halide perovskites (MHPs) are excellent semiconductors that have led to breakthroughs in applications in thinfilmsolar cells, detectors, and light-emitting diodes due to their remarkable optoelectronic properties and defect tolerance.However, the performance and stability of MHP-based devices are significantly influenced by their microstructures includingthe formation of defects, composition fluctuations, structural inhomogeneity, etc. Transmission electron microscopy(TEM) is a powerful tool for direct observation of microstructure at the atomic-scale resolution and has been used to correlatethe microstructure and performance of MHP-based devices. In this review, we highlight the application of TEMtechniques in revealing the microstructures of MHP thin films at the atomic scale. The results provide critical understandingof the performance of MHP devices and guide the design of strategies for improving the performance and stability ofMHP devices. 展开更多
关键词 PEROVSKITE DEFECT INHOMOGENEITY transmission electron microscopy
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Probing the Nucleation and Growth Kinetics of Bismuth Nanoparticles via In-situ Transmission Electron Microscopy
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作者 王浪 李超凡 +3 位作者 RAN Maojin YUAN Manman 胡执一 LI Yu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第4期877-887,共11页
The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of interme... The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of intermediate state structure during nucleation and growth.In this work,the evolution process of bismuth nanoparticles induced by electron beam was revealed by in-situ transmission electron microscopy(TEM)at atomic scale.The experimental results demonstrate that the size,stable surface and crystallographic defect have important influences on the growth of Bi nanoparticles.Two non-classical growth paths including single crystal growth and polycrystalline combined growth,as well as,corresponding layer-by-layer growth mechanism along{012}stable crystal plane of Bi nanoparticles with dodecahedron structure were revealed by in-situ TEM directly.These results provide important guidance and a new approach for in-depth understanding of the nucleation and growth kinetics of nanoparticles. 展开更多
关键词 bismuth nanoparticles crystal growth transmission electron microscopy in-situ electron microscopy
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Characterization of local chemical ordering and deformation behavior in high entropy alloys by transmission electron microscopy
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作者 Qiuhong Liu Qing Du +7 位作者 Xiaobin Zhang Yuan Wu Andrey A.Rempel Xiangyang Peng Xiongjun Liu Hui Wang Wenli Song Zhaoping Lü 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期877-886,共10页
Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed composit... Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied locations.Transmission electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex alloys.In this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of HEAs.By using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was clarified.Moreover,the perspective related to application of TEM techniques in HEAs are also discussed. 展开更多
关键词 high entropy alloys transmission electron microscopy short-range ordering deformation mechanisms
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Capturing the non-equilibrium state in light–matter–free-electron interactions through ultrafast transmission electron microscopy
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作者 汪文韬 孙帅帅 +5 位作者 李俊 郑丁国 黄思远 田焕芳 杨槐馨 李建奇 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期88-101,共14页
Ultrafast transmission electron microscope(UTEM) with the multimodality of time-resolved diffraction, imaging,and spectroscopy provides a unique platform to reveal the fundamental features associated with the interact... Ultrafast transmission electron microscope(UTEM) with the multimodality of time-resolved diffraction, imaging,and spectroscopy provides a unique platform to reveal the fundamental features associated with the interaction between free electrons and matter. In this review, we summarize the principles, instrumentation, and recent developments of the UTEM and its applications in capturing dynamic processes and non-equilibrium transient states. The combination of the transmission electron microscope with a femtosecond laser via the pump–probe method guarantees the high spatiotemporal resolution, allowing the investigation of the transient process in real, reciprocal and energy spaces. Ultrafast structural dynamics can be studied by diffraction and imaging methods, revealing the coherent acoustic phonon generation and photoinduced phase transition process. In the energy dimension, time-resolved electron energy-loss spectroscopy enables the examination of the intrinsic electronic dynamics of materials, while the photon-induced near-field electron microscopy extends the application of the UTEM to the imaging of optical near fields with high real-space resolution. It is noted that light–free-electron interactions have the ability to shape electron wave packets in both longitudinal and transverse directions, showing the potential application in the generation of attosecond electron pulses and vortex electron beams. 展开更多
关键词 ultrafast transmission electron microscopy non-equilibrium structural dynamics photo-induced phase transition free-electron–photon interactions
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In situ observation of the electrochemical behavior of Li–CO_(2)/O_(2)batteries in an environmental transmission electron microscope
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作者 Peng Jia Yunna Guo +5 位作者 Dongliang Chen Jingming Yao Xuedong Zhang Jianguo Lu Yuqing Qiao Liqiang Zhang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第4期244-255,共12页
Li–CO_(2)/O_(2)batteries,a promising energy storage technology,not only provide ultrahigh discharge capacity but also capture CO_(2)and turn it into renewable energy.Their electrochemical reaction pathways'ambigu... Li–CO_(2)/O_(2)batteries,a promising energy storage technology,not only provide ultrahigh discharge capacity but also capture CO_(2)and turn it into renewable energy.Their electrochemical reaction pathways'ambiguity,however,creates a hurdle for their practical application.This study used copper selenide(CuSe)nanosheets as the air cathode medium in an environmental transmission electron microscope to in situ study Li–CO_(2)/O_(2)(mix CO_(2)as well as O_(2)at a volume ratio of 1:1)and Li–O_(2)batteries as well as Li–CO_(2)batteries.Primary discharge reactions take place successively in the Li–CO_(2)/O_(2)–CuSe nanobattery:(I)4Li^(+)+O_(2)+4e^(−)→2Li_(2)O;(II)Li_(2)O+CO_(2)→Li_(2)CO_(3).The charge reaction proceeded via(III)2Li_(2)CO_(3)→4Li^(+)+2CO_(2)+O_(2)+4e^(−).However,Li–O_(2)and Li–CO_(2)nanobatteries showed poor cycling stability,suggesting the difficulty in the direct decomposition of the discharge product.The fluctuations of the Li–CO_(2)/O_(2)battery's electrochemistry were also shown to depend heavily on O_(2).The CuSe‐based Li–CO_(2)/O_(2)battery showed exceptional electrochemical performance.The Li^–CO_(2)/O_(2)battery offered a discharge capacity apex of 15,492 mAh g^(−1) and stable cycling 60 times at 100 mA g^(−1).Our research offers crucial insight into the electrochemical behavior of Li–CO_(2)/O_(2),Li–O_(2),and Li–CO_(2)nanobatteries,which may help the creation of high‐performance Li–CO_(2)/O_(2)batteries for energy storage applications. 展开更多
关键词 CuSe nanosheets electrochemical reaction in situ environmental transmission electron microscopy Li-CO_(2)battery Li-CO_(2)/O_(2)battery Li-O_(2)battery
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A transmission electron microscopy study of the diversity of Candida albicans cells induced by Euphorbia hirta L.leaf extract in vitro 被引量:3
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作者 Abu Arra Basma Zakaria Zuraini Sreenivasan Sasidharan 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2011年第1期20-22,共3页
Objective:To determine the major changes in the microstructure of Candida albicans(C. albicans) after treatment with Euphorbia hirta(E.hirta) L.leaf extract.Methods:Transmission electron microscopy was used to study t... Objective:To determine the major changes in the microstructure of Candida albicans(C. albicans) after treatment with Euphorbia hirta(E.hirta) L.leaf extract.Methods:Transmission electron microscopy was used to study the ultrastructural changes caused by E.hirta extract on C. albicans cells al various exposure time.Results:It was found that the main abnormalities were the alterations in morphology,lysis and complete collapse of the yeast cells after 36 h of exposure to the extract.Whereas the control cultures showed a typical morphology of Candida with a uniform central density,typically structured nucleus,and a cytoplasm with several elements of endomembrane system and enveloped by a regular,intact cell wall.Conclusions:The significant antifungal activity shown by this methanol extract of E.hirta L.suggests its potential against infections caused by C.albicans.The extract may be developed as an anticandidal agent. 展开更多
关键词 CANDIDA ALBICANS EUPHORBIA hirta L. transmission electron microscopy Anticandidal agent
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扫描电镜中透射-反射式STEM明场成像装置的研制及应用
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作者 赵学平 侯小虎 +3 位作者 刘飞 梁绍波 崔晓明 白朴存 《电子显微学报》 CAS CSCD 北大核心 2024年第2期208-214,共7页
本文研制了一套透射-反射式扫描透射(STEM)明场成像装置,该装置使用背散射电子探头接收经过铂片反射的透射电子信号,可安装在FEI Quanta FEG系列扫描电镜中实现STEM明场成像。分别以埃洛石、Au@ZIF-8纳米颗粒和喷金乳胶标样验证自制STE... 本文研制了一套透射-反射式扫描透射(STEM)明场成像装置,该装置使用背散射电子探头接收经过铂片反射的透射电子信号,可安装在FEI Quanta FEG系列扫描电镜中实现STEM明场成像。分别以埃洛石、Au@ZIF-8纳米颗粒和喷金乳胶标样验证自制STEM明场成像装置的实用性。结果表明:埃洛石STEM明场像的衬度与透射电镜中STEM明场像一致,管腔和管壁具有明显的衬度差异,可以清晰辨识管腔结构;在Au@ZIF-8纳米颗粒的STEM明场像中,Au颗粒衬度较暗,ZIF-8衬度较亮,通过两者之间的衬度差异可以观察到核壳结构;喷金乳胶标样上纳米金颗粒之间可识别的最小距离为2.03 nm,进一步验证了自制STEM明场成像装置具有较高的分辨率。 展开更多
关键词 扫描电镜 扫描透射电子显微镜 明场像 成像装置 图像衬度
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A review of in situ transmission electron microscopy study on the switching mechanism and packaging reliability in non-volatile memory 被引量:3
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作者 Xin Yang Chen Luo +7 位作者 Xiyue Tian Fang Liang Yin Xia Xinqian Chen Chaolun Wang Steve Xin Liang Xing Wu Junhao Chu 《Journal of Semiconductors》 EI CAS CSCD 2021年第1期62-76,共15页
Non-volatile memory(NVM)devices with non-volatility and low power consumption properties are important in the data storage field.The switching mechanism and packaging reliability issues in NVMs are of great research i... Non-volatile memory(NVM)devices with non-volatility and low power consumption properties are important in the data storage field.The switching mechanism and packaging reliability issues in NVMs are of great research interest.The switching process in NVM devices accompanied by the evolution of microstructure and composition is fast and subtle.Transmission electron microscopy(TEM)with high spatial resolution and versatile external fields is widely used in analyzing the evolution of morphology,structures and chemical compositions at atomic scale.The various external stimuli,such as thermal,electrical,mechanical,optical and magnetic fields,provide a platform to probe and engineer NVM devices inside TEM in real-time.Such advanced technologies make it possible for an in situ and interactive manipulation of NVM devices without sacrificing the resolution.This technology facilitates the exploration of the intrinsic structure-switching mechanism of NVMs and the reliability issues in the memory package.In this review,the evolution of the functional layers in NVM devices characterized by the advanced in situ TEM technology is introduced,with intermetallic compounds forming and degradation process investigated.The principles and challenges of TEM technology on NVM device study are also discussed. 展开更多
关键词 MEMORY transmission electron microscopy in situ characterization PACKAGE RELIABILITY
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Transmission Electron Microscopy as a Powerful Tool for Investigating Lithium-ion Battery Materials 被引量:2
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作者 LIN Cong LI Jian-Yuan +1 位作者 WANG Chong-Min PAN Feng 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2019年第12期2015-2019,共5页
Transmission electron microscopy(TEM) stands out as one of the most powerful tools for characterizing materials at multiple scales and dimensions. This unique technique has nowadays been widely employed in investigati... Transmission electron microscopy(TEM) stands out as one of the most powerful tools for characterizing materials at multiple scales and dimensions. This unique technique has nowadays been widely employed in investigating the lithium-ion battery(LIB) materials. The present perspective paper focuses on several LIB related aspects that are recently revealed by using TEM. Finally, we present outlook on the future directions of TEM for LIB research and development. 展开更多
关键词 transmission electron microscopy lithium-ion batteries STRUCTURES PROPERTIES
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High-resolution Transmission Electron Microscopy Characterization of the Structure of Cu Precipitate in a Thermal-aged Multicomponent Steel 被引量:1
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作者 Lizhan Han Qingdong Liu Jianfeng Gu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2019年第5期117-124,共8页
High-dispersed nanoscale Cu precipitates often contribute to extremely high strength due to precipitation hardening,and whereas usually lead to degraded toughness for especially ferritic steels.Hence,it is important t... High-dispersed nanoscale Cu precipitates often contribute to extremely high strength due to precipitation hardening,and whereas usually lead to degraded toughness for especially ferritic steels.Hence,it is important to understand the formation behaviors of the Cu precipitates.High-resolution transmission electron microscopy(TEM)is utilized to investigate the structure of Cu precipitates thermally formed in a high-strength low-alloy(HSLA)steel.The Cu precipitates were generally formed from solid solution and at the crystallographic defects such as martensite lath boundaries and dislocations.The Cu precipitates in the same aging condition have various structure of BCC,9 R and FCC,and the structural evolution does not greatly correlate with the actual sizes.The presence of different structures in an individual Cu precipitate is observed,which reflects the structural transformation occurring locally to relax the strain energy.The multiply additions in the steel possibly make the Cu precipitation more complex compared to the binary or the ternary Fe-Cu alloys with Ni or Mn additions.This research gives constructive suggestions on alloying design of Cu-bearing alloy steels. 展开更多
关键词 CU PRECIPITATE High-resolution transmission electron microscopy THERMAL aging HIGH-STRENGTH low-alloy STEEL
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Lattice Distortion Analysis Directly from High Resolution Transmission Electron Microscopy Images —the LADIA Program Package 被引量:2
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作者 Y.Rau, N.Y.Jin-Phillipp and F.PhillippMax-Planck-Institut fiir Metallforschung, Heisenbergstrasse 1, Stuttgart, D-70569, Germany 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第2期135-138,共4页
Direct strain mapping from high resolution transmission electron microscopy images is possible for coherent structures. At proper imaging conditions the intensity peaks in the image have a constant spatial relationshi... Direct strain mapping from high resolution transmission electron microscopy images is possible for coherent structures. At proper imaging conditions the intensity peaks in the image have a constant spatial relationship with the projected atom columns. This allows the determination of the geometry of the projected unit cell without comparison with image simulations. The fast procedure is particularly suited for the analysis of large areas. The software package LADIA is written in the PV-WAVE code and provides all necessary tools for image processing and analysis. Image intensity peaks are determined by a cross-correlation technique, which avoids problems from noise in the low spatial frequency range. The lower limit of strain that can be detected at a sampling rate of 44 pixels/nm is≈2%. 展开更多
关键词 High-resolution transmission electron microscopy Distortion analysis
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Scanning transmission electron microscopy: A review of high angle annular dark field and annular bright field imaging and applications in lithium-ion batteries 被引量:1
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作者 Yu-Xin Tong Qing-Hua Zhang Lin Gu 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第6期23-34,共12页
Scanning transmission electron microscopy(STEM) has been shown as powerful tools for material characterization,especially after the appearance of aberration-corrector which greatly enhances the resolution of STEM. H... Scanning transmission electron microscopy(STEM) has been shown as powerful tools for material characterization,especially after the appearance of aberration-corrector which greatly enhances the resolution of STEM. High angle annular dark field(HAADF) and annular bright field(ABF) imaging of the aberration-corrected STEM are widely used due to their high-resolution capabilities and easily interpretable image contrasts. However, HAADF mode of the STEM is still limited in detecting light elements due to the weak electron-scattering power. ABF mode of the STEM could detect light and heavy elements simultaneously, providing unprecedented opportunities for probing unknown structures of materials. Atomiclevel structure investigation of materials has been achieved by means of these imaging modes, which is invaluable in many fields for either improving properties of materials or developing new materials. This paper aims to provide a introduction of HAADF and ABF imaging techniques and reviews their applications in characterization of cathode materials, study of electrochemical reaction mechanisms, and exploring the effective design of lithium-ion batteries(LIBs). The future prospects of the STEM are also discussed. 展开更多
关键词 scanning transmission electron microscopy high angle annular dark field annular bright field lithium-ion batteries
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Recent progress on advanced transmission electron microscopy characterization for halide perovskite semiconductors 被引量:1
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作者 Xiaomei Wu Xiaoxing Ke Manling Sui 《Journal of Semiconductors》 EI CAS CSCD 2022年第4期67-81,共15页
Halide perovskites are strategically important in the field of energy materials. Along with the rapid development of the materials and related devices, there is an urgent need to understand the structure–property rel... Halide perovskites are strategically important in the field of energy materials. Along with the rapid development of the materials and related devices, there is an urgent need to understand the structure–property relationship from nanoscale to atomic scale. Much effort has been made in the past few years to overcome the difficulty of imaging limited by electron dose,and to further extend the investigation towards operando conditions. This review is dedicated to recent studies of advanced transmission electron microscopy(TEM) characterizations for halide perovskites. The irradiation damage caused by the interaction of electron beams and perovskites under conventional imaging conditions are first summarized and discussed. Low-dose TEM is then discussed, including electron diffraction and emerging techniques for high-resolution TEM(HRTEM) imaging. Atomic-resolution imaging, defects identification and chemical mapping on halide perovskites are reviewed. Cryo-TEM for halide perovskites is discussed, since it can readily suppress irradiation damage and has been rapidly developed in the past few years. Finally, the applications of in-situ TEM in the degradation study of perovskites under environmental conditions such as heating,biasing, light illumination and humidity are reviewed. More applications of emerging TEM characterizations are foreseen in the coming future, unveiling the structural origin of halide perovskite’s unique properties and degradation mechanism under operando conditions, so to assist the design of a more efficient and robust energy material. 展开更多
关键词 organic–inorganic hybrid perovskite solar cell materials energy materials scanning electron microscopy transmission electron microscopy irradiation damage
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Movement of Dislocations in the Sub-Surface of a Polycrystalline Metal by Cavitation Peening Observed by Transmission Electron Microscopy 被引量:1
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作者 Osamu Takakuwa Akihiko Chiba Hitoshi Soyama 《Materials Sciences and Applications》 2015年第2期140-144,共5页
The impact produced when cavitation bubbles collapse can be utilized to modify surfaces in the same way as shot peening and it is called cavitation peening (CP). CP is one of a number of surface modification technique... The impact produced when cavitation bubbles collapse can be utilized to modify surfaces in the same way as shot peening and it is called cavitation peening (CP). CP is one of a number of surface modification techniques used to improve the fatigue strength of metallic materials by introducing compressive residual stress. Although it has been shown by an X-ray diffraction method that CP decreases the micro-strain related to dislocations in the sub-surface of a polycrystalline material, the mechanism for this decrease is unclear. In this paper, the movement of dislocations by CP was observed using transmission electron microscopy (TEM). 展开更多
关键词 Microstructure transmission electron microscopy DISLOCATION SURFACE Modification CAVITATION
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3-1 Transmission Electron Microscopy Investigations of Bubble Formation in Grain Boundaries of He-implanted Polycrystalline SiC 被引量:2
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作者 Li Bingsheng Du Yangyang Wang Zhiguang 《IMP & HIRFL Annual Report》 2015年第1期89-90,共2页
Because of the low cross-section for neutron capture and its excellent structural, chemical and mechanical stability, silicon carbide (SiC) is an important material with application in the development of nuclear energ... Because of the low cross-section for neutron capture and its excellent structural, chemical and mechanical stability, silicon carbide (SiC) is an important material with application in the development of nuclear energy and waste technologies. For example, in the fourth generation of fission reactors, such as high-temperature gas-cooled reactors and gas-cooled fast reactors, TRISO-coated particle fuel is designed, because this fuel is very robust with no failures anticipated during irradiation and under accident conditions. 展开更多
关键词 transmission electron microscopy
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Multidimensional images and aberrations in STEM
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作者 Eric R.Hoglund Andrew R.Lupini 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期68-74,共7页
Recent advances in scanning transmission electron microscopy(STEM)have led to increased development of multidimensional STEM imaging modalities and novel image reconstruction methods.This interest arises because the m... Recent advances in scanning transmission electron microscopy(STEM)have led to increased development of multidimensional STEM imaging modalities and novel image reconstruction methods.This interest arises because the main electron lens in a modern transmission electron microscope usually has a diffraction-space information limit that is significantly better than the real-space resolution of the same lens.This state-of-affairs is sometimes shared by other scattering methods in modern physics and contributes to a broader excitement surrounding multidimensional techniques that scan a probe while recording diffraction-space images,such as ptychography and scanning nano-beam diffraction.However,the contrasting resolution in the two spaces raises the question as to what is limiting their effective performance.Here,we examine this paradox by considering the effects of aberrations in both image and diffraction planes,and likewise separate the contributions of pre-and post-sample aberrations.This consideration provides insight into aberration-measurement techniques and might also indicate improvements for super-resolution techniques. 展开更多
关键词 SCANNING transmission electron microscopy (Stem) ABERRATIONS
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Probing nickelate superconductors at atomic scale:A STEM review
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作者 Yihan Lei Yanghe Wang +4 位作者 Jiahao Song Jinxin Ge Dirui Wu Yingli Zhang Changjian Li 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期2-11,共10页
The discovery of nickelate superconductors,including doped infinite-layer(IL)nickelates RNiO2(R=La,Pr,Nd),layered square-planar nickelate Nd6Ni5O12,and the Ruddlesden–Popper(RP)phase La3Ni2O7,has spurred immense inte... The discovery of nickelate superconductors,including doped infinite-layer(IL)nickelates RNiO2(R=La,Pr,Nd),layered square-planar nickelate Nd6Ni5O12,and the Ruddlesden–Popper(RP)phase La3Ni2O7,has spurred immense interest in fundamental research and potential applications.Scanning transmission electron microscopy(STEM)has proven crucial for understanding structure–property correlations in these diverse nickelate superconducting systems.In this review,we summarize the key findings from various modes of STEM,elucidating the mechanism of different nickelate superconductors.We also discuss future perspectives on emerging STEM techniques for unraveling the pairing mechanism in the“nickel age”of superconductivity. 展开更多
关键词 scanning transmission electron microscopy SUPERCONDUCTIVITY epitaxial thin films NICKELATES
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Nanoscale cathodoluminescence spectroscopy probing the nitride quantum wells in an electron microscope
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作者 刘哲彤 刘秉尧 +8 位作者 梁冬冬 李晓梅 李晓敏 陈莉 朱瑞 徐军 魏同波 白雪冬 高鹏 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期144-149,共6页
To gain further understanding of the luminescence properties of multiquantum wells and the factors affecting them on a microscopic level,cathodoluminescence combined with scanning transmission electron microscopy and ... To gain further understanding of the luminescence properties of multiquantum wells and the factors affecting them on a microscopic level,cathodoluminescence combined with scanning transmission electron microscopy and spectroscopy was used to measure the luminescence of In_(0.15)Ga_(0.85)N five-period multiquantum wells.The lattice-composition-energy relationship was established with the help of energy-dispersive x-ray spectroscopy,and the bandgaps of In_(0.15)Ga_(0.85)N and GaN in multiple quantum wells were extracted by electron energy loss spectroscopy to understand the features of cathodoluminescence spectra.The luminescence differences between different periods of multiquantum wells and the effects of defects such as composition fluctuation and dislocations on the luminescence of multiple quantum wells were revealed.Our study establishing the direct relationship between the atomic structure of In_(x)Ga_(1-x)N multiquantum wells and photoelectric properties provides useful information for nitride applications. 展开更多
关键词 nitride multiquantum wells defect CATHODOLUMINESCENCE scanning transmission electron microscopy
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Symmetry quantification and segmentation in STEM imaging through Zernike moments
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作者 Jiadong Dan Cheng Zhang +1 位作者 赵晓续 N.Duane Loh 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第8期39-48,共10页
We present a method using Zernike moments for quantifying rotational and reflectional symmetries in scanning transmission electron microscopy(STEM)images,aimed at improving structural analysis of materials at the atom... We present a method using Zernike moments for quantifying rotational and reflectional symmetries in scanning transmission electron microscopy(STEM)images,aimed at improving structural analysis of materials at the atomic scale.This technique is effective against common imaging noises and is potentially suited for low-dose imaging and identifying quantum defects.We showcase its utility in the unsupervised segmentation of polytypes in a twisted bilayer TaS_(2),enabling accurate differentiation of structural phases and monitoring transitions caused by electron beam effects.This approach enhances the analysis of structural variations in crystalline materials,marking a notable advancement in the characterization of structures in materials science. 展开更多
关键词 scanning transmission electron microscopy(Stem) SYMMETRY SEGMENTATION
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Characterization of swift heavy ion tracks in MoS2 by transmission electron microscopy
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作者 Li-Jun Xu Peng-Fei Zhai +6 位作者 Sheng-Xia Zhang Jian Zeng Pei-Pei Hu Zong-Zhen Li Li Liu You-Mei Sun Jie Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第10期401-405,共5页
The various morphologies of tracks in MoS2 irradiated by swift heavy ions at normal and 30° incidence with 9.5–25.0 MeV/u 86Kr, 129Xe, 181Ta, and 209Bi ions were investigated by transmission electron microscopy.... The various morphologies of tracks in MoS2 irradiated by swift heavy ions at normal and 30° incidence with 9.5–25.0 MeV/u 86Kr, 129Xe, 181Ta, and 209Bi ions were investigated by transmission electron microscopy. The diameter of ion tracks increases from 1.9 nm to 4.5 nm with increasing electronic energy loss. The energy loss threshold of the track formation in MoS2 is predicted as about 9.7 keV/nm based on the thermal spike model and it seems consistent with the experimental results. It is shown that the morphology of ion tracks is related to the penetration length of ions in MoS2. The formation process of ion tracks is discussed based on the cooperative process of outflow and recrystallization of the molten phase during rapid quenching. 展开更多
关键词 ion track MOS2 transmission electron microscopy(tem) RECRYSTALLIZATION
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