Pub Date : 2025-09-13DOI: 10.1016/j.ultramic.2025.114226
Xuecheng Zhang , Zixin Li , Bin Zhang , Wenchao Meng , Yuefei Zhang , Chaojie Gu , Xianjue Ye , Ze Zhang
The scanning electron microscope (SEM) is a crucial tool for characterizing material microstructures, and it is renowned for its high resolution and depth of field. However, SEM image quality is affected by the scanning speed and resolution settings. When using SEM to capture fast-changing dynamic processes and other specific tasks, maintaining high image quality while using fast scanning mode is often tricky. To address these challenges, this paper introduces introduce an efficient two-stage diffusion model for accelerated SEM image super-resolution named ETDMS. The image denoising and super-resolution were divided into independent tasks based on SEM imaging principles and completed in two separate stages. Specifically, in Stage 2, a conditional lightweight encoder–decoder architecture SR network is proposed to replace the large U-Net in the traditional diffusion model and combine it with accelerated sampling technology to improve image generation efficiency. Experimental results prove that compared with previous super-resolution methods, the images generated by ETDMS significantly improve evaluation parameters, subjective visual quality, and detail generation.
{"title":"ETDMS: Efficient two-stage diffusion model for accelerated SEM image super-resolution","authors":"Xuecheng Zhang , Zixin Li , Bin Zhang , Wenchao Meng , Yuefei Zhang , Chaojie Gu , Xianjue Ye , Ze Zhang","doi":"10.1016/j.ultramic.2025.114226","DOIUrl":"10.1016/j.ultramic.2025.114226","url":null,"abstract":"<div><div>The scanning electron microscope (SEM) is a crucial tool for characterizing material microstructures, and it is renowned for its high resolution and depth of field. However, SEM image quality is affected by the scanning speed and resolution settings. When using SEM to capture fast-changing dynamic processes and other specific tasks, maintaining high image quality while using fast scanning mode is often tricky. To address these challenges, this paper introduces introduce an efficient two-stage diffusion model for accelerated SEM image super-resolution named ETDMS. The image denoising and super-resolution were divided into independent tasks based on SEM imaging principles and completed in two separate stages. Specifically, in Stage 2, a conditional lightweight encoder–decoder architecture SR network is proposed to replace the large U-Net in the traditional diffusion model and combine it with accelerated sampling technology to improve image generation efficiency. Experimental results prove that compared with previous super-resolution methods, the images generated by ETDMS significantly improve evaluation parameters, subjective visual quality, and detail generation.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"278 ","pages":"Article 114226"},"PeriodicalIF":2.0,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-13DOI: 10.1016/j.ultramic.2025.114224
Antonín Jaroš , Johann Toyfl , Andrea Pupić , Benjamin Czasch , Giovanni Boero , Isobel C. Bicket , Philipp Haslinger
Coherent spin resonance methods such as nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy have led to spectrally highly sensitive, non-invasive quantum imaging techniques with groundbreaking applications in fields such as medicine, biology, and physics. Meanwhile, transmission electron microscopy (TEM) offers detailed investigations with sub-atomic resolution, but often inflicts significant radiation damage. Here we exploit synergies and report on an integration of ESR spectroscopy in a TEM. Our miniaturized ESR setup, optimized for microscopic sample sizes, is implemented on a standard TEM sample holder and leverages the strong magnetic field of the TEM polepiece to align and energetically separate spin states. This integration will facilitate in situ studies of spin systems and their dynamics, quantum materials, radicals, electrochemical reactions, and radiation damage — properties that have, until now, been difficult to access using conventional electron microscopic tools. Moreover, this development marks a significant technological advancement towards microwave-driven quantum spin studies with a highly controlled electron probe at the nanoscale.
{"title":"Electron spin resonance spectroscopy in a transmission electron microscope","authors":"Antonín Jaroš , Johann Toyfl , Andrea Pupić , Benjamin Czasch , Giovanni Boero , Isobel C. Bicket , Philipp Haslinger","doi":"10.1016/j.ultramic.2025.114224","DOIUrl":"10.1016/j.ultramic.2025.114224","url":null,"abstract":"<div><div>Coherent spin resonance methods such as nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy have led to spectrally highly sensitive, non-invasive quantum imaging techniques with groundbreaking applications in fields such as medicine, biology, and physics. Meanwhile, transmission electron microscopy (TEM) offers detailed investigations with sub-atomic resolution, but often inflicts significant radiation damage. Here we exploit synergies and report on an integration of ESR spectroscopy in a TEM. Our miniaturized ESR setup, optimized for microscopic sample sizes, is implemented on a standard TEM sample holder and leverages the strong magnetic field of the TEM polepiece to align and energetically separate spin states. This integration will facilitate <em>in situ</em> studies of spin systems and their dynamics, quantum materials, radicals, electrochemical reactions, and radiation damage — properties that have, until now, been difficult to access using conventional electron microscopic tools. Moreover, this development marks a significant technological advancement towards microwave-driven quantum spin studies with a highly controlled electron probe at the nanoscale.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"278 ","pages":"Article 114224"},"PeriodicalIF":2.0,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145092543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-08DOI: 10.1016/j.ultramic.2025.114237
Tahsinul Huq , Yew Hoong Wong , Joon Huang Chuah , Chee-Keong Tan , Shuye Zhang
A novel method for determining aluminum thin film thickness using top view SEM and EDX measurements has been developed. Electron beam simulations are used as the reference training data to feed into a machine learning algorithm, which once trained can predict the thickness of the aluminum thin film from EDX characteristic x-ray count measurements for a set of three accelerating voltages. Unlike previous techniques which rely on a reference pure material sample or substrate signal to compare to, this method compares instead using ratios of EDX x-ray signals using different accelerating voltages. Since no substrate signal is required, the layer(s) below the aluminum thin film may be any material. High prediction accuracy was obtained for the training and test data for most data points, below 10 % for thicknesses above 40 nm on average, though some large errors remained. Investigation of the lateral dispersion of the incident electron beams showed that lateral dispersion increased with accelerating voltage. Since measurement of higher thicknesses requires higher accelerating voltages, the minimum feature size that can be accurately measured increases for higher thicknesses. Limitations include the requirement for aluminum to be the top layer, the requirement for consistency of beam current, low signal and excessive noise at low values of accelerating voltage, and the need to make many measurements at different voltages if the approximate range of the thin film thickness is not initially known.
{"title":"Novel technique for aluminum thin film thickness measurement using top view SEM-EDX in conjunction with electron beam simulation and machine learning","authors":"Tahsinul Huq , Yew Hoong Wong , Joon Huang Chuah , Chee-Keong Tan , Shuye Zhang","doi":"10.1016/j.ultramic.2025.114237","DOIUrl":"10.1016/j.ultramic.2025.114237","url":null,"abstract":"<div><div>A novel method for determining aluminum thin film thickness using top view SEM and EDX measurements has been developed. Electron beam simulations are used as the reference training data to feed into a machine learning algorithm, which once trained can predict the thickness of the aluminum thin film from EDX characteristic x-ray count measurements for a set of three accelerating voltages. Unlike previous techniques which rely on a reference pure material sample or substrate signal to compare to, this method compares instead using ratios of EDX x-ray signals using different accelerating voltages. Since no substrate signal is required, the layer(s) below the aluminum thin film may be any material. High prediction accuracy was obtained for the training and test data for most data points, below 10 % for thicknesses above 40 nm on average, though some large errors remained. Investigation of the lateral dispersion of the incident electron beams showed that lateral dispersion increased with accelerating voltage. Since measurement of higher thicknesses requires higher accelerating voltages, the minimum feature size that can be accurately measured increases for higher thicknesses. Limitations include the requirement for aluminum to be the top layer, the requirement for consistency of beam current, low signal and excessive noise at low values of accelerating voltage, and the need to make many measurements at different voltages if the approximate range of the thin film thickness is not initially known.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"278 ","pages":"Article 114237"},"PeriodicalIF":2.0,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.ultramic.2025.114229
Ka Yin Lee , Elliot K. Beutler , Tifany Q. Crisolo , David J. Masiello , Maureen J. Lagos
Using vibrational electron energy loss spectroscopy (vib-EELS) combined with numerical modeling, we investigate the physical mechanisms governing the phonon coupling between a spherical particle sustaining multipolar surface phonon modes and an underlying thin film. Depending upon their dielectric composition, a variety of hybrid phonon modes arise in the EEL spectrum due to the interaction between polarization charges in the particle and film. Mirror charge effects and phonon mode hybridization are the active mechanisms acting on dielectric and metallic-type films, respectively. Processes beyond dipole-dipole interactions are required to describe the sphere-film coupling.
{"title":"Substrate matters: Coupled phonon modes of a spherical particle on a substrate probed with EELS","authors":"Ka Yin Lee , Elliot K. Beutler , Tifany Q. Crisolo , David J. Masiello , Maureen J. Lagos","doi":"10.1016/j.ultramic.2025.114229","DOIUrl":"10.1016/j.ultramic.2025.114229","url":null,"abstract":"<div><div>Using vibrational electron energy loss spectroscopy (vib-EELS) combined with numerical modeling, we investigate the physical mechanisms governing the phonon coupling between a spherical particle sustaining multipolar surface phonon modes and an underlying thin film. Depending upon their dielectric composition, a variety of hybrid phonon modes arise in the EEL spectrum due to the interaction between polarization charges in the particle and film. Mirror charge effects and phonon mode hybridization are the active mechanisms acting on dielectric and metallic-type films, respectively. Processes beyond dipole-dipole interactions are required to describe the sphere-film coupling.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"278 ","pages":"Article 114229"},"PeriodicalIF":2.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-26DOI: 10.1016/j.ultramic.2025.114227
Fan Peng , Xuemei Song , Yiling Huang , Xingyu Jin , Yuqing Jiang , Yue Sun , Yi Zeng
Electron backscatter diffraction (EBSD) is an important technique based on the scanning electron microscope (SEM) that provides a wide range of crystallographic information. There are limited available pattern indexing methods and most of them are mastered by commercial instrument manufacturers, which may probably restrict the sharing and development of indexing techniques. In this study, we present a new EBSD pattern indexing method based on a three-dimensional parameter space. This method extends the characterization of characteristic triangles into a three-dimensional parameter space. This work details the procedure of the new indexing algorithm. The utility of this new method is demonstrated using experimental patterns captured from a cubic yttria-stabilized zirconia (YSZ) bulk sample. Compared with commercial indexing results, the new method shows excellent consistency and achieves better indexing performance at grain boundaries.
{"title":"A new EBSD indexing method with enhanced grain boundary indexing performance using a three-dimensional parameter space","authors":"Fan Peng , Xuemei Song , Yiling Huang , Xingyu Jin , Yuqing Jiang , Yue Sun , Yi Zeng","doi":"10.1016/j.ultramic.2025.114227","DOIUrl":"10.1016/j.ultramic.2025.114227","url":null,"abstract":"<div><div>Electron backscatter diffraction (EBSD) is an important technique based on the scanning electron microscope (SEM) that provides a wide range of crystallographic information. There are limited available pattern indexing methods and most of them are mastered by commercial instrument manufacturers, which may probably restrict the sharing and development of indexing techniques. In this study, we present a new EBSD pattern indexing method based on a three-dimensional parameter space. This method extends the characterization of characteristic triangles into a three-dimensional parameter space. This work details the procedure of the new indexing algorithm. The utility of this new method is demonstrated using experimental patterns captured from a cubic yttria-stabilized zirconia (YSZ) bulk sample. Compared with commercial indexing results, the new method shows excellent consistency and achieves better indexing performance at grain boundaries.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"277 ","pages":"Article 114227"},"PeriodicalIF":2.0,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1016/j.ultramic.2025.114228
Po-Cheng Kung , Rui Feng , Peter Liaw , Jian-Min Zuo , Jessica Krogstad
Complex face-centered-cubic (FCC) alloys frequently display chemical short-range ordering (CSRO), which can be detected through the analysis of diffuse scattering. However, the interpretation of diffuse scattering is complicated by the presence of defects and thermal diffuse scattering, making it extremely challenging to distinguish CSRO using conventional scattering techniques. This complexity has sparked intense debates regarding the origin of specific diffuse-scattering signals, such as those observed at 1/3{422} and 1/2{311} positions. To address this challenge, we introduce the method of spatial fluctuation and correlation (FluCor) analysis of local diffuse scattering captured using Four-Dimensional Scanning Transmission Electron Microscopy (4D-STEM). We demonstrate our methodology using a solution-treated (CrCoNi)93Al4Ti2Nb medium-entropy alloy (MEA) and show that the FluCor analysis can differentiate diffuse scattering of different origins. The results reveal two sets of overlapping diffuse-scattering signals at the 1/3{422} and 1/2{311} positions in the studied MEA and link both to non-CSRO origins. Specifically, the heterogeneous-domain diffuse-scattering signals are attributed to nanoscale planar defects, while the homogeneous diffuse-scattering of the matrix is best explained by thermal-diffuse scattering. The principles underlying our fluctuation and correlation analysis of diffuse scattering are general and broadly applicable to order-disordered crystals, including various complex alloy systems. This versatility promises to yield valuable insights into the interplay between microstructural characteristics and CSRO behavior in a wide range of materials, potentially resolving long-standing debates in the field.
{"title":"Differentiating electron diffuse scattering via 4D-STEM spatial fluctuation and correlation analysis in complex FCC alloys","authors":"Po-Cheng Kung , Rui Feng , Peter Liaw , Jian-Min Zuo , Jessica Krogstad","doi":"10.1016/j.ultramic.2025.114228","DOIUrl":"10.1016/j.ultramic.2025.114228","url":null,"abstract":"<div><div>Complex face-centered-cubic (FCC) alloys frequently display chemical short-range ordering (CSRO), which can be detected through the analysis of diffuse scattering. However, the interpretation of diffuse scattering is complicated by the presence of defects and thermal diffuse scattering, making it extremely challenging to distinguish CSRO using conventional scattering techniques. This complexity has sparked intense debates regarding the origin of specific diffuse-scattering signals, such as those observed at 1/3{422} and 1/2{311} positions. To address this challenge, we introduce the method of spatial fluctuation and correlation (FluCor) analysis of local diffuse scattering captured using Four-Dimensional Scanning Transmission Electron Microscopy (4D-STEM). We demonstrate our methodology using a solution-treated (CrCoNi)<sub>93</sub>Al<sub>4</sub>Ti<sub>2</sub>Nb medium-entropy alloy (MEA) and show that the FluCor analysis can differentiate diffuse scattering of different origins. The results reveal two sets of overlapping diffuse-scattering signals at the 1/3{422} and 1/2{311} positions in the studied MEA and link both to non-CSRO origins. Specifically, the heterogeneous-domain diffuse-scattering signals are attributed to nanoscale planar defects, while the homogeneous diffuse-scattering of the matrix is best explained by thermal-diffuse scattering. The principles underlying our fluctuation and correlation analysis of diffuse scattering are general and broadly applicable to order-disordered crystals, including various complex alloy systems. This versatility promises to yield valuable insights into the interplay between microstructural characteristics and CSRO behavior in a wide range of materials, potentially resolving long-standing debates in the field.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"278 ","pages":"Article 114228"},"PeriodicalIF":2.0,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-23DOI: 10.1016/j.ultramic.2025.114225
Songge Li , Nicolas Gauquelin , Hoelen L. Lalandec Robert , Arno Annys , Chuang Gao , Christoph Hofer , Timothy J. Pennycook , Jo Verbeeck
The single sideband (SSB) framework of analytical electron ptychography can account for the presence of residual geometrical aberrations induced by the probe-forming lens. However, the accuracy of this aberration correction method is highly sensitive to the invested electron dose, in part due to the necessity of phase unwrapping. In this work, we thus propose two strategies to improve the performance in low-dose conditions: confining phase unwrapping within the sidebands and selecting only well-unwrapped sidebands for calculating aberration coefficients. These strategies are validated through SSB reconstructions of both simulated and experimental 4D-STEM datasets of monolayer tungsten diselenide (WSe2). A comparison of results demonstrates significant improvements in Poisson noise tolerance, making aberration correction more robust and reliable for low-dose imaging.
{"title":"Improving the low-dose performance of aberration correction in single sideband ptychography","authors":"Songge Li , Nicolas Gauquelin , Hoelen L. Lalandec Robert , Arno Annys , Chuang Gao , Christoph Hofer , Timothy J. Pennycook , Jo Verbeeck","doi":"10.1016/j.ultramic.2025.114225","DOIUrl":"10.1016/j.ultramic.2025.114225","url":null,"abstract":"<div><div>The single sideband (SSB) framework of analytical electron ptychography can account for the presence of residual geometrical aberrations induced by the probe-forming lens. However, the accuracy of this aberration correction method is highly sensitive to the invested electron dose, in part due to the necessity of phase unwrapping. In this work, we thus propose two strategies to improve the performance in low-dose conditions: confining phase unwrapping within the sidebands and selecting only well-unwrapped sidebands for calculating aberration coefficients. These strategies are validated through SSB reconstructions of both simulated and experimental 4D-STEM datasets of monolayer tungsten diselenide (WSe<sub>2</sub>). A comparison of results demonstrates significant improvements in Poisson noise tolerance, making aberration correction more robust and reliable for low-dose imaging.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"277 ","pages":"Article 114225"},"PeriodicalIF":2.0,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-19DOI: 10.1016/j.ultramic.2025.114222
Florian Castioni , Patrick Quéméré , Sergi Cuesta , Vincent Delaye , Pascale Bayle-Guillemaud , Eva Monroy , Eric Robin , Nicolas Bernier
Recent advancements in high-resolution spectroscopy analyses within the scanning transmission electron microscope (STEM) have paved the way for measuring the concentration of chemical species in crystalline materials at the atomic scale. However, several artifacts complicate the direct interpretation of experimental data. For instance, in the case of energy-dispersive X-ray (EDX) spectroscopy, the linear dependency of local X-ray emission on composition is disrupted by channeling effects and cross-talk during electron beam propagation. To address these challenges, it becomes necessary to adopt an approach that combines experimental data with inelastic scattering simulations. This method aims to account for the effects of electron beam propagation on X-ray emission, essentially determining the quantity and the spatial origin of the collected signal. In this publication, we propose to assess the precision and sensitivity limits of this approach in a practical case study involving a focused ion beam (FIB)-prepared III-N multilayers device. The device features nominally pure ∼1.5-nm-wide GaN quantum wells surrounded by AlGaN barriers containing a low concentration of aluminum (∼5 at%). By employing atomic-scale EDX acquisitions based on the averaging of more than several thousand frames, calibrated factors combined with a multilayer X-ray absorption correction model for quantification, and by comparing the X-ray radiation obtained from the quantum well with a reference 10-nm-wide structure, we demonstrate that the quantitative impact of beam propagation on chemical composition can be precisely accounted for, resulting in a composition sensitivity at the atomic scale as low as 0.25 at%. Finally, practical aspects to achieve this high precision level are discussed, particularly in terms of inelastic multislice simulation, uncertainty determination, and sample quality.
{"title":"Impact of electron beam propagation on high-resolution quantitative chemical analysis of 1-nm-wide GaN/AlGaN quantum wells","authors":"Florian Castioni , Patrick Quéméré , Sergi Cuesta , Vincent Delaye , Pascale Bayle-Guillemaud , Eva Monroy , Eric Robin , Nicolas Bernier","doi":"10.1016/j.ultramic.2025.114222","DOIUrl":"10.1016/j.ultramic.2025.114222","url":null,"abstract":"<div><div>Recent advancements in high-resolution spectroscopy analyses within the scanning transmission electron microscope (STEM) have paved the way for measuring the concentration of chemical species in crystalline materials at the atomic scale. However, several artifacts complicate the direct interpretation of experimental data. For instance, in the case of energy-dispersive X-ray (EDX) spectroscopy, the linear dependency of local X-ray emission on composition is disrupted by channeling effects and cross-talk during electron beam propagation. To address these challenges, it becomes necessary to adopt an approach that combines experimental data with inelastic scattering simulations. This method aims to account for the effects of electron beam propagation on X-ray emission, essentially determining the quantity and the spatial origin of the collected signal. In this publication, we propose to assess the precision and sensitivity limits of this approach in a practical case study involving a focused ion beam (FIB)-prepared III-N multilayers device. The device features nominally pure ∼1.5-nm-wide GaN quantum wells surrounded by AlGaN barriers containing a low concentration of aluminum (∼5 at%). By employing atomic-scale EDX acquisitions based on the averaging of more than several thousand frames, calibrated <span><math><mrow><mi>ζ</mi></mrow></math></span> factors combined with a multilayer X-ray absorption correction model for quantification, and by comparing the X-ray radiation obtained from the quantum well with a reference 10-nm-wide structure, we demonstrate that the quantitative impact of beam propagation on chemical composition can be precisely accounted for, resulting in a composition sensitivity at the atomic scale as low as <span><math><mo>±</mo></math></span>0.25 at%. Finally, practical aspects to achieve this high precision level are discussed, particularly in terms of inelastic multislice simulation, uncertainty determination, and sample quality.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"277 ","pages":"Article 114222"},"PeriodicalIF":2.0,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have developed an operando laser-based photoemission electron microscope (laser-PEEM) with a ferroelectric characterization system. A Sawyer-Tower circuit was implemented to measure the polarization–voltage (P–V) characteristics of ferroelectric devices. Using this system, we successfully obtained the well-defined P–V hysteresis loops for a ferroelectric capacitor incorporating Hf0.5Zr0.5O2 (HZO), reproducing the typical field-cycling characteristics of HZO capacitors. After dielectric breakdown caused by field-cycling stress, we visualized a conduction filament through the top electrode without any destructive processing. Additionally, we successfully observed polarization contrast through the top electrode of an oxide semiconductor (InZnOx). These results indicate that our operando laser-PEEM system is a powerful tool for visualizing conduction filaments after dielectric breakdown, the ferroelectric polarization contrasts, and electronic state distribution of materials implemented in ferroelectric devices, including ferroelectric field-effect transistors and ferroelectric tunnel junctions.
{"title":"Breakdown and polarization contrasts in ferroelectric devices observed by operando laser-based photoemission electron microscopy with the AC/DC electrical characterization system","authors":"Hirokazu Fujiwara , Yuki Itoya , Masaharu Kobayashi , Cédric Bareille , Toshiyuki Taniuchi","doi":"10.1016/j.ultramic.2025.114221","DOIUrl":"10.1016/j.ultramic.2025.114221","url":null,"abstract":"<div><div>We have developed an <em>operando</em> laser-based photoemission electron microscope (laser-PEEM) with a ferroelectric characterization system. A Sawyer-Tower circuit was implemented to measure the polarization–voltage (<em>P</em>–<em>V</em>) characteristics of ferroelectric devices. Using this system, we successfully obtained the well-defined <em>P</em>–<em>V</em> hysteresis loops for a ferroelectric capacitor incorporating Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> (HZO), reproducing the typical field-cycling characteristics of HZO capacitors. After dielectric breakdown caused by field-cycling stress, we visualized a conduction filament through the top electrode without any destructive processing. Additionally, we successfully observed polarization contrast through the top electrode of an oxide semiconductor (InZnO<em><sub>x</sub></em>). These results indicate that our <em>operando</em> laser-PEEM system is a powerful tool for visualizing conduction filaments after dielectric breakdown, the ferroelectric polarization contrasts, and electronic state distribution of materials implemented in ferroelectric devices, including ferroelectric field-effect transistors and ferroelectric tunnel junctions.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"277 ","pages":"Article 114221"},"PeriodicalIF":2.0,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144840734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-10DOI: 10.1016/j.ultramic.2025.114223
Ranhao Zhang , Yuan Shen , Xueming Li
A tomogram is reconstructed from the micrographs of the tilt series using cryo-electron tomography (cryoET). Reconstruction frequently integrates image processing steps, such as filtering and contrast transfer function (CTF) correction, to support the downstream analysis of cellular and viral structures. Most image processing steps are based on Fourier space analysis, which is theoretically more efficient to be implemented in Fourier space than in real space. However, the substantial dimensions of tomograms present significant challenges for reconstruction and processing in Fourier space. Consequently, real-space reconstruction is prevalent in current practice. In this study, we proposed a Fourier-space algorithm for tomogram reconstruction, named MUltiple Slice Technique (MUST). MUST considers a tomogram composed of multiple parallel slices, with each slice independently reconstructed in Fourier space. A weighting strategy was used to enable MUST to achieve reconstruction compatible with real-space methods, including weighted back-projection (WBP) and the simultaneous iterative reconstruction technique (SIRT). A three-dimensional CTF model was formulated as pairs of conjugate central paraboloids in Fourier space and subsequently implemented for CTF correction in MUST. Alias-free reconstruction and pixel-level parallel computation are key features of MUST, demonstrated through tomogram-based subtomogram averaging at near-atomic resolutions.
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