Pub Date : 2025-12-08DOI: 10.1016/j.ultramic.2025.114299
Harry J. Whitlow , Rattanaporn Norarat , Robert J.W. Frost , Aishee Ghosh , Donruedee Toyen , Deepanwita Bose , Aaron McLaughlin , Francois Villinger
Fourier optics provides a powerful and objective approach to handling Poissonian statistics in images. Fourier optics has been used to develop an approach to segment microbeam images into tissue and void (non-tissue) areas (e.g. villi, crypts, blood vessels and lymph canals etc.). Image segmentation is important in order to accurately measure the major element composition and thickness of biological sections. The method is based on comparing the spatial frequency of non-zero pixels in a reference void with tissue regions using a convolution method. The method automatically and conservatively segments tissue areas and uses no free-parameters. Since the method is based on spatial frequencies it can be used over a wide span of image counting statistics.
{"title":"A Fourier-optical approach for segmentation of ion microprobe images into tissue and non-tissue covered areas","authors":"Harry J. Whitlow , Rattanaporn Norarat , Robert J.W. Frost , Aishee Ghosh , Donruedee Toyen , Deepanwita Bose , Aaron McLaughlin , Francois Villinger","doi":"10.1016/j.ultramic.2025.114299","DOIUrl":"10.1016/j.ultramic.2025.114299","url":null,"abstract":"<div><div>Fourier optics provides a powerful and objective approach to handling Poissonian statistics in images. Fourier optics has been used to develop an approach to segment microbeam images into tissue and void (non-tissue) areas (e.g. villi, crypts, blood vessels and lymph canals etc.). Image segmentation is important in order to accurately measure the major element composition and thickness of biological sections. The method is based on comparing the spatial frequency of non-zero pixels in a reference void with tissue regions using a convolution method. The method automatically and conservatively segments tissue areas and uses no free-parameters. Since the method is based on spatial frequencies it can be used over a wide span of image counting statistics.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"281 ","pages":"Article 114299"},"PeriodicalIF":2.0,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145769267","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 : 2025-12-07DOI: 10.1016/j.ultramic.2025.114295
Sangjun Kang , Hyeyoung Cho , Maximilian Töllner , Vanessa Wollersen , Di Wang , Hionsuck Baik , Marie Joëlle Perera , Omar Adjaoud , Karsten Albe , Christian Kübel , Xiaoke Mu
Electron pair distribution function (ePDF), combined with four-dimensional scanning transmission electron microscopy (4D-STEM), provides a powerful approach for uncovering detailed information about the local atomic structure and structural variations in disordered materials. However, achieving high accuracy in ePDF analysis requires careful control of experimental and instrumental parameters. In this study, we systematically investigate the effect of key electron optical, measurement and processing parameters on ePDF analysis using simulations as the primary tool, complemented by experimental validation. Specifically, we examine the influence of diffraction angle range, beam convergence semi-angle, detector pixel resolution, sample thickness (multiple scattering effect), noise, and electron beam precession on the resulting ePDF. By integrating multi-slice electron diffraction simulations with experimental diffraction data, we identify optimal conditions for accurate ePDF extraction and provide practical guidelines to improve analysis precision and reliability. These insights contribute to refining ePDF techniques, particularly for applications involving amorphous and nanostructured materials.
{"title":"Validating electron pair distribution function analysis: The role of multiple scattering, beam, measurement, and processing parameters","authors":"Sangjun Kang , Hyeyoung Cho , Maximilian Töllner , Vanessa Wollersen , Di Wang , Hionsuck Baik , Marie Joëlle Perera , Omar Adjaoud , Karsten Albe , Christian Kübel , Xiaoke Mu","doi":"10.1016/j.ultramic.2025.114295","DOIUrl":"10.1016/j.ultramic.2025.114295","url":null,"abstract":"<div><div>Electron pair distribution function (ePDF), combined with four-dimensional scanning transmission electron microscopy (4D-STEM), provides a powerful approach for uncovering detailed information about the local atomic structure and structural variations in disordered materials. However, achieving high accuracy in ePDF analysis requires careful control of experimental and instrumental parameters. In this study, we systematically investigate the effect of key electron optical, measurement and processing parameters on ePDF analysis using simulations as the primary tool, complemented by experimental validation. Specifically, we examine the influence of diffraction angle range, beam convergence semi-angle, detector pixel resolution, sample thickness (multiple scattering effect), noise, and electron beam precession on the resulting ePDF. By integrating multi-slice electron diffraction simulations with experimental diffraction data, we identify optimal conditions for accurate ePDF extraction and provide practical guidelines to improve analysis precision and reliability. These insights contribute to refining ePDF techniques, particularly for applications involving amorphous and nanostructured materials.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"281 ","pages":"Article 114295"},"PeriodicalIF":2.0,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737640","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 : 2025-12-07DOI: 10.1016/j.ultramic.2025.114296
Chang-Gi Lee , Byeong-Gyu Chae , I-Jun Ro , Kyuseon Jang , Nak-Kyoon Kim , Jae-Pyoung Ahn , Eric Woods , Jaemin Ahn , Seong Yong Park , Baptiste Gault , Se-Ho Kim
Atom probe tomography (APT) enables near-atomic-scale, three-dimensional elemental mapping through controlled field evaporation of surface atoms, triggered by the combined application of a DC voltage with either voltage or laser pulses. As selected laser wavelengths in atom probes transitioned from near-infrared (1050–1064 nm) toward shorter wavelengths, such as green (532 nm) and near-ultraviolet (NUV 355 nm), the quality of data improved and the range of analyzable materials expanded significantly. Recently, a new commercial atom probe (Invizo 6000) employing a deep ultraviolet (DUV) laser wavelength of 257.5 nm has been introduced. Invizo 6000 incorporates several new design elements, such as dual laser beam, einzel lens, and flat counter electrode. However, despite these substantial design modifications, systematic studies comparing its performance with conventional local electrode atom probe (LEAP) systems across different classes of materials remain scarce. In this study, various materials, including metals and oxides, were examined using commercial LEAP 5000 and Invizo 6000. The quality of the data obtained from both instruments was systematically evaluated using four key metrics: background levels, detection events, ion detection histograms, and mass-resolving power. Additionally, applying a thin coating to the prepared APT specimens was found to enhance data quality.
{"title":"Performance evaluation of deep-ultraviolet laser-assisted Invizo 6000 and near-ultraviolet laser-assisted LEAP 5000 for a range of material systems","authors":"Chang-Gi Lee , Byeong-Gyu Chae , I-Jun Ro , Kyuseon Jang , Nak-Kyoon Kim , Jae-Pyoung Ahn , Eric Woods , Jaemin Ahn , Seong Yong Park , Baptiste Gault , Se-Ho Kim","doi":"10.1016/j.ultramic.2025.114296","DOIUrl":"10.1016/j.ultramic.2025.114296","url":null,"abstract":"<div><div>Atom probe tomography (APT) enables near-atomic-scale, three-dimensional elemental mapping through controlled field evaporation of surface atoms, triggered by the combined application of a DC voltage with either voltage or laser pulses. As selected laser wavelengths in atom probes transitioned from near-infrared (1050–1064 nm) toward shorter wavelengths, such as green (532 nm) and near-ultraviolet (NUV 355 nm), the quality of data improved and the range of analyzable materials expanded significantly. Recently, a new commercial atom probe (Invizo 6000) employing a deep ultraviolet (DUV) laser wavelength of 257.5 nm has been introduced. Invizo 6000 incorporates several new design elements, such as dual laser beam, einzel lens, and flat counter electrode. However, despite these substantial design modifications, systematic studies comparing its performance with conventional local electrode atom probe (LEAP) systems across different classes of materials remain scarce. In this study, various materials, including metals and oxides, were examined using commercial LEAP 5000 and Invizo 6000. The quality of the data obtained from both instruments was systematically evaluated using four key metrics: background levels, detection events, ion detection histograms, and mass-resolving power. Additionally, applying a thin coating to the prepared APT specimens was found to enhance data quality.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"281 ","pages":"Article 114296"},"PeriodicalIF":2.0,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737642","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 : 2025-12-07DOI: 10.1016/j.ultramic.2025.114300
Yangfan Li , Yue Pan , Xincheng Lei , Weiwei Chen , Yang Shen , Mengshu Ge , Xiaozhi Liu , Dong Su
High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) is a vital tool for characterizing single-atom catalysts (SACs). However, reliable elemental identification of different atoms remains challenging because the signal intensity of HAADF depends strongly on defocus and other imaging parameters, potentially ruining the Z-contrast of atoms at different depths. In this work, we investigated the influence of the vertical position of atoms (defocus), support thickness, interatomic height, convergence, and collection angles via multi-slice simulations on a model system of Fe/Pt atoms on amorphous carbon supports. Our calculation shows that at a convergence angle of 28 mrad, a defocus of 8.5 nm can cause Fe and Pt atoms to be indistinguishable. At a larger convergence angle, this critical indistinguishable defocus can be even shorter. To address this limitation, we propose a Multi-Defocus Fusion (MDF) method, retrieving the Z-contrast from serial images from multiple defocus. Experimental validation on a Fe/Pt SAC sample confirms the effectiveness of MDF, yielding clearly separated intensity histograms corresponding to Fe and Pt atoms. This work presents a robust, easy-to-implement strategy for accurate single-atom identification, offering valuable guidance for the accelerated screening and rational design of high-performance SACs.
{"title":"Differentiation of distinct single atoms via multi‑defocus fusion method","authors":"Yangfan Li , Yue Pan , Xincheng Lei , Weiwei Chen , Yang Shen , Mengshu Ge , Xiaozhi Liu , Dong Su","doi":"10.1016/j.ultramic.2025.114300","DOIUrl":"10.1016/j.ultramic.2025.114300","url":null,"abstract":"<div><div>High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) is a vital tool for characterizing single-atom catalysts (SACs). However, reliable elemental identification of different atoms remains challenging because the signal intensity of HAADF depends strongly on defocus and other imaging parameters, potentially ruining the Z-contrast of atoms at different depths. In this work, we investigated the influence of the vertical position of atoms (defocus), support thickness, interatomic height, convergence, and collection angles via multi-slice simulations on a model system of Fe/Pt atoms on amorphous carbon supports. Our calculation shows that at a convergence angle of 28 mrad, a defocus of 8.5 nm can cause Fe and Pt atoms to be indistinguishable. At a larger convergence angle, this critical indistinguishable defocus can be even shorter. To address this limitation, we propose a Multi-Defocus Fusion (MDF) method, retrieving the Z-contrast from serial images from multiple defocus. Experimental validation on a Fe/Pt SAC sample confirms the effectiveness of MDF, yielding clearly separated intensity histograms corresponding to Fe and Pt atoms. This work presents a robust, easy-to-implement strategy for accurate single-atom identification, offering valuable guidance for the accelerated screening and rational design of high-performance SACs.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"281 ","pages":"Article 114300"},"PeriodicalIF":2.0,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737641","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 : 2025-11-30DOI: 10.1016/j.ultramic.2025.114292
Ovidiu Cretu, Koji Kimoto
We report on the development of a new 100 MHz high-speed scan controller for the electron microscope, using programmable hardware. By using a spiral scan pattern in order to work around the limitations of the scan coils, we show that this controller is able to acquire undistorted images with a frame time of 0.9 ms. The controller’s scan signal and timing control is used to optimize regular (sawtooth) scanning, in order to reduce image distortions at high speeds. Finally, we implement a dose-driven acquisition method, which lowers the required dose and optimizes its distribution, while maintaining the contrast mechanism of the detector.
{"title":"Development of a 100 MHz scan controller for the electron microscope","authors":"Ovidiu Cretu, Koji Kimoto","doi":"10.1016/j.ultramic.2025.114292","DOIUrl":"10.1016/j.ultramic.2025.114292","url":null,"abstract":"<div><div>We report on the development of a new 100 MHz high-speed scan controller for the electron microscope, using programmable hardware. By using a spiral scan pattern in order to work around the limitations of the scan coils, we show that this controller is able to acquire undistorted images with a frame time of 0.9 ms. The controller’s scan signal and timing control is used to optimize regular (sawtooth) scanning, in order to reduce image distortions at high speeds. Finally, we implement a dose-driven acquisition method, which lowers the required dose and optimizes its distribution, while maintaining the contrast mechanism of the detector.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"281 ","pages":"Article 114292"},"PeriodicalIF":2.0,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145693176","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 : 2025-11-29DOI: 10.1016/j.ultramic.2025.114280
Lei Yu , Weishi Wan , Xiaodong Yang , Meng Li , Takanori Koshikawa , Masahiko Suzuki , Tsuneo Yasue , Xiuguang Jin , Yoshikazu Takeda , Rudolf M. Tromp , Yaowen Liu , Hans-Joachim Elmers , Wen-Xin Tang
Magnetic structures down to the nanometer scale have drawn increasing attention due to their fundamental interests and potential applications. In general, the magnetic structure of a system tends to stay in the state with the lowest energy as different interactions compete with each other. Here we report the direct observation of a meta-stable Omega state with double vortices of the same circularity in a nanoscale Fe island on a W(110) substrate. The process indicates that this metastable state is formed by two isolated islands merging during annealing, while keeping their original vortex state. Micromagnetic simulations confirm the possibility of this metastable state.
{"title":"Direct observation of meta-stable magnetization states in Fe/W(110) nanostructures","authors":"Lei Yu , Weishi Wan , Xiaodong Yang , Meng Li , Takanori Koshikawa , Masahiko Suzuki , Tsuneo Yasue , Xiuguang Jin , Yoshikazu Takeda , Rudolf M. Tromp , Yaowen Liu , Hans-Joachim Elmers , Wen-Xin Tang","doi":"10.1016/j.ultramic.2025.114280","DOIUrl":"10.1016/j.ultramic.2025.114280","url":null,"abstract":"<div><div>Magnetic structures down to the nanometer scale have drawn increasing attention due to their fundamental interests and potential applications. In general, the magnetic structure of a system tends to stay in the state with the lowest energy as different interactions compete with each other. Here we report the direct observation of a meta-stable Omega state with double vortices of the same circularity in a nanoscale Fe island on a W(110) substrate. The process indicates that this metastable state is formed by two isolated islands merging during annealing, while keeping their original vortex state. Micromagnetic simulations confirm the possibility of this metastable state.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"281 ","pages":"Article 114280"},"PeriodicalIF":2.0,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145693175","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}
Atomic Force Microscopy (AFM), as a scanning probe microscopy technique, has been extensively utilized for nanoscale structural characterization, mechanical property quantification, and in-situ electromagnetic field measurements with high spatial resolution. However, the primary limitations hindering the widespread application of AFM include its relatively low scanning velocity, intricate parameter optimization requirements, and the necessity for highly skilled operators to achieve optimal imaging resolution. In this paper, a novel fuzzy amplitude-modulated PI (Proportional-Integral) control methodology is proposed for AFM adaptive control systems, incorporating dynamically adjusted proportional and integral gain parameters to effectively mitigate measurement inaccuracies. Experimental characterization demonstrates that the proposed fuzzy control scheme effectively confines amplitude error to approximately 60 pm under operational conditions of 10 Hz scan rate and 40 μm scan size. This methodology establishes a systematic framework for optimizing parameter configuration in AFM, while simultaneously addressing the critical challenge of achieving high-speed performance in scanning probe microscopy applications.
{"title":"Fast tapping mode atomic force microscopy based on fuzzy PI controller","authors":"Lijia Ji , Renjie Gui , Jinbo Chen , Xuhui Zhang , Gengliang Chen","doi":"10.1016/j.ultramic.2025.114281","DOIUrl":"10.1016/j.ultramic.2025.114281","url":null,"abstract":"<div><div>Atomic Force Microscopy (AFM), as a scanning probe microscopy technique, has been extensively utilized for nanoscale structural characterization, mechanical property quantification, and in-situ electromagnetic field measurements with high spatial resolution. However, the primary limitations hindering the widespread application of AFM include its relatively low scanning velocity, intricate parameter optimization requirements, and the necessity for highly skilled operators to achieve optimal imaging resolution. In this paper, a novel fuzzy amplitude-modulated PI (Proportional-Integral) control methodology is proposed for AFM adaptive control systems, incorporating dynamically adjusted proportional and integral gain parameters to effectively mitigate measurement inaccuracies. Experimental characterization demonstrates that the proposed fuzzy control scheme effectively confines amplitude error to approximately 60 pm under operational conditions of 10 Hz scan rate and 40 μm scan size. This methodology establishes a systematic framework for optimizing parameter configuration in AFM, while simultaneously addressing the critical challenge of achieving high-speed performance in scanning probe microscopy applications.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"281 ","pages":"Article 114281"},"PeriodicalIF":2.0,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145651725","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 : 2025-11-24DOI: 10.1016/j.ultramic.2025.114282
Aaditya Bhat, Colin Gilgenbach, Junghwa Kim, Michael Xu, Menglin Zhu, James M. LeBeau
Here, we evaluate multislice electron ptychography as a tool for depth-resolved atomic-resolution characterization of point defects, using silicon carbide as a case study. Through multislice electron scattering simulations and multislice ptychographic reconstructions, we investigate the phase contrast arising from individual silicon vacancies, antisite defects, and a wide range of substitutional transition metal dopants (VSi to WSi), as well as their potential detectability. Simulating defect types, positions, and microscope conditions, we show that isolated point defects can be located within a unit cell along the sample’s depth. The influence of electron energy, dose, defocus, and convergence semi-angle is also explored to determine their role in governing defect contrast. These results guide experiments aimed at analyzing point defects using multislice electron ptychography.
{"title":"Sensitivity of multislice electron ptychography to point defects: A case study in SiC","authors":"Aaditya Bhat, Colin Gilgenbach, Junghwa Kim, Michael Xu, Menglin Zhu, James M. LeBeau","doi":"10.1016/j.ultramic.2025.114282","DOIUrl":"10.1016/j.ultramic.2025.114282","url":null,"abstract":"<div><div>Here, we evaluate multislice electron ptychography as a tool for depth-resolved atomic-resolution characterization of point defects, using silicon carbide as a case study. Through multislice electron scattering simulations and multislice ptychographic reconstructions, we investigate the phase contrast arising from individual silicon vacancies, antisite defects, and a wide range of substitutional transition metal dopants (V<sub>Si</sub> to W<sub>Si</sub>), as well as their potential detectability. Simulating defect types, positions, and microscope conditions, we show that isolated point defects can be located within a unit cell along the sample’s depth. The influence of electron energy, dose, defocus, and convergence semi-angle is also explored to determine their role in governing defect contrast. These results guide experiments aimed at analyzing point defects using multislice electron ptychography.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"280 ","pages":"Article 114282"},"PeriodicalIF":2.0,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615331","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 : 2025-11-24DOI: 10.1016/j.ultramic.2025.114284
Austin Irish , Lukas Hrachowina , David Alcer , Magnus Borgström , Rainer Timm
Surface physics play an outsized role in nanostructured electronic devices such as solar cells. Semiconductor nanowires are perfect candidates for advanced solar cells due to their outstanding light absorption properties and their flexibility in axially stacking materials of different doping and band gap. Due to nanowire geometry, however, their surfaces dominate device performance and at the same time are challenging to investigate. Kelvin probe force microscopy (KPFM), an atomic force microscopy (AFM)-based method, provides a unique structural and electrical characterization even in unconventional 3D geometries. We demonstrate a high-resolution, non-destructive AFM technique for directly measuring nanowires within an array and still on their growth substrate. This in situ approach ensures measurement integrity and relevance while preserving the structures for subsequent measurement and processing. When compared with electron beam-induced current, cross-sectional KPFM is both more surface sensitive and less destructive. Utilizing such a cross-sectional approach facilitates rapid and comprehensive characterization of nanoelectronic surfaces.
{"title":"On the Edge: In situ Kelvin probe AFM on InP nanowire arrays","authors":"Austin Irish , Lukas Hrachowina , David Alcer , Magnus Borgström , Rainer Timm","doi":"10.1016/j.ultramic.2025.114284","DOIUrl":"10.1016/j.ultramic.2025.114284","url":null,"abstract":"<div><div>Surface physics play an outsized role in nanostructured electronic devices such as solar cells. Semiconductor nanowires are perfect candidates for advanced solar cells due to their outstanding light absorption properties and their flexibility in axially stacking materials of different doping and band gap. Due to nanowire geometry, however, their surfaces dominate device performance and at the same time are challenging to investigate. Kelvin probe force microscopy (KPFM), an atomic force microscopy (AFM)-based method, provides a unique structural and electrical characterization even in unconventional 3D geometries. We demonstrate a high-resolution, non-destructive AFM technique for directly measuring nanowires within an array and still on their growth substrate. This <em>in situ</em> approach ensures measurement integrity and relevance while preserving the structures for subsequent measurement and processing. When compared with electron beam-induced current, cross-sectional KPFM is both more surface sensitive and less destructive. Utilizing such a cross-sectional approach facilitates rapid and comprehensive characterization of nanoelectronic surfaces.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"281 ","pages":"Article 114284"},"PeriodicalIF":2.0,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145678990","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 : 2025-11-24DOI: 10.1016/j.ultramic.2025.114283
Yang Liu , Hongsheng Shi , Siyuan Shen , Yuan Lu , Shuchen Zhang , Jingyi Yu , Yi Yu
Atomic-scale imaging of radiation-sensitive materials has been a challenge for both materials science and life science. While low-dose transmission electron microscopy (TEM) is particularly useful for minimizing the radiation damage, the noisy images with poor resolution make it extremely difficult for the purpose of fine structure analysis. Here, this work presents a phase retrieval method to achieve high-quality atomic-scale imaging of radiation-sensitive materials under low-dose TEM conditions. By integrating neural fields (NF) with traditional exit wave reconstruction (EWR), it is able to reveal atomic details from limited low-dose experimental data. Taking the radiation-sensitive organic–inorganic hybrid halide perovskite CHNHPbI (MAPbI) as an example, the EWR-NF method demonstrates superior performance in reconstructing the pristine atomic structure using as few as just three low-dose images, which is beyond the limits of conventional methods. In this manner, EWR-NF enables higher temporal resolution to reveal intermediate states during irradiation-induced decomposition. An example of stacking of MAPbI with its as-decomposed product is shown. EWR-NF offers a promising tool for atomic-level structure analysis of sensitive halide perovskites and understanding irradiation-induced structure changes, with implications for a wide range of applications in materials science and beyond.
{"title":"Neural field enhanced phase retrieval of atomic-scale structural dynamics in radiation sensitive materials","authors":"Yang Liu , Hongsheng Shi , Siyuan Shen , Yuan Lu , Shuchen Zhang , Jingyi Yu , Yi Yu","doi":"10.1016/j.ultramic.2025.114283","DOIUrl":"10.1016/j.ultramic.2025.114283","url":null,"abstract":"<div><div>Atomic-scale imaging of radiation-sensitive materials has been a challenge for both materials science and life science. While low-dose transmission electron microscopy (TEM) is particularly useful for minimizing the radiation damage, the noisy images with poor resolution make it extremely difficult for the purpose of fine structure analysis. Here, this work presents a phase retrieval method to achieve high-quality atomic-scale imaging of radiation-sensitive materials under low-dose TEM conditions. By integrating neural fields (NF) with traditional exit wave reconstruction (EWR), it is able to reveal atomic details from limited low-dose experimental data. Taking the radiation-sensitive organic–inorganic hybrid halide perovskite CH<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>NH<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>PbI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> (MAPbI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>) as an example, the EWR-NF method demonstrates superior performance in reconstructing the pristine atomic structure using as few as just three low-dose images, which is beyond the limits of conventional methods. In this manner, EWR-NF enables higher temporal resolution to reveal intermediate states during irradiation-induced decomposition. An example of stacking of MAPbI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> with its as-decomposed product is shown. EWR-NF offers a promising tool for atomic-level structure analysis of sensitive halide perovskites and understanding irradiation-induced structure changes, with implications for a wide range of applications in materials science and beyond.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"280 ","pages":"Article 114283"},"PeriodicalIF":2.0,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615330","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}
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