Ultramicroscopy最新文献_第4页

Towards continuous time-dependent tomography: implementation and evaluation of continuous acquisition schemes in electron tomography 迈向连续时间相关断层扫描：电子断层扫描中连续采集方案的实现和评估

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-07-06 DOI: 10.1016/j.ultramic.2025.114207

Timothy M. Craig , Robin Girod , Gail Vinnacombe-Willson , Luis M. Liz-Marzán , Sara Bals

{"title":"Towards continuous time-dependent tomography: implementation and evaluation of continuous acquisition schemes in electron tomography","authors":"Timothy M. Craig , Robin Girod , Gail Vinnacombe-Willson , Luis M. Liz-Marzán , Sara Bals","doi":"10.1016/j.ultramic.2025.114207","DOIUrl":"10.1016/j.ultramic.2025.114207","url":null,"abstract":"<div><div>Electron tomography is a microscopy technique that allows the three-dimensional (3D) characterization of nanomaterials by reconstructing a 3D volume from a series of two-dimensional (2D) projection images acquired at different viewing angles. In a transmission electron microscope (TEM), the change in angle is achieved by tilting the sample holder and conventionally follows an incremental tilt scheme. Images are typically acquired between <span><math><mo>±</mo></math></span> 60–80°, as dictated by the TEM geometry, and in small, 2–3°, increments to minimize sample shifts and facilitate acquisition and post-processing. This tilt scheme unfortunately performs poorly when time resolution is necessary, i.e., when as many 3D reconstructions as possible of the same object within a given time are desired. Golden ratio scanning (GRS) and binary decomposition (BD) have been proposed in other tomographies because they allow consecutive reconstructions to share some projections. However, due to practical considerations, they have seen limited usage in electron tomography. In this work, we present optimized implementations of GRS and BD for electron tomography with corrections for alignment, backlash, and angular uniformity. These tilt schemes were compared with incremental acquisition for simulated and experimental datasets in static or dynamic contexts. Experimentally, GRS and BD required 2–3 times longer acquisition time, and resulted in a 2 times increase in electron dose compared to the incremental scheme, thus confirming the incremental scheme as the method to be favored for static applications. In dynamic applications, our results suggest that a time vs. spatial resolution tradeoff should be considered. Nonetheless, GRS and BD schemes would achieve up to 30x higher 3D frame rate, showing promise toward time-dependent electron tomography.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"277 ","pages":"Article 114207"},"PeriodicalIF":2.1,"publicationDate":"2025-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655327","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}

引用次数: 0

High-energy resolution monochromated STEM-EELS mapping across large areas 高能量分辨率单色STEM-EELS大面积制图

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-07-05 DOI: 10.1016/j.ultramic.2025.114202

Caleb Whittier , Nabil D. Bassim

{"title":"High-energy resolution monochromated STEM-EELS mapping across large areas","authors":"Caleb Whittier , Nabil D. Bassim","doi":"10.1016/j.ultramic.2025.114202","DOIUrl":"10.1016/j.ultramic.2025.114202","url":null,"abstract":"<div><div>Scanning transmission electron microscopy (STEM) allows for high spatial-resolution analysis of materials and, when coupled with electron energy loss spectroscopy (EELS), becomes capable of providing substantial insight into both chemical and optical properties. In recent years, focus has moved towards understanding material properties at the atomic level using EELS. However, there are still significant barriers when attempting to perform high-energy resolution monochromated STEM-EELS analysis on large structures. Off-axis distortions cause additional aberrations to couple into the spectrometer when scanning across large regions. This often limits STEM-EELS mapping to small areas to maintain the energy resolution or requires sacrificing this resolution to spectrum maps spanning multiple microns. We propose here a methodology enabling low-loss STEM-EELS spectrum mapping to be performed over tens to hundreds of microns while maintaining high energy-resolution through modification of the EELS collection conditions. This is accomplished not only through careful alignment of the scan/descan coils, but, more importantly, through implementation of elongated camera lengths that effectively magnify the object over the EELS entrance aperture, cutting out higher order aberrations and reducing shifts on the spectrometer.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"276 ","pages":"Article 114202"},"PeriodicalIF":2.1,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597064","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}

引用次数: 0

Data-efficient 4D-STEM in SEM: Beyond 2D materials to metallic materials 扫描电镜中数据高效的4D-STEM：从二维材料到金属材料

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-07-01 DOI: 10.1016/j.ultramic.2025.114203

Ujjval Bansal , Amit Sharma , Barbara Putz , Christoph Kirchlechner , Subin Lee

{"title":"Data-efficient 4D-STEM in SEM: Beyond 2D materials to metallic materials","authors":"Ujjval Bansal , Amit Sharma , Barbara Putz , Christoph Kirchlechner , Subin Lee","doi":"10.1016/j.ultramic.2025.114203","DOIUrl":"10.1016/j.ultramic.2025.114203","url":null,"abstract":"<div><div>Four-dimensional scanning transmission electron microscopy (4D-STEM) is a powerful tool that allows for the simultaneous acquisition of spatial and diffraction information, driven by recent advancements in direct electron detector technology. Although 4D-STEM has been predominantly developed for and used in conventional TEM and STEM, efforts are being made to implement the technique in scanning electron microscopy (SEM). In this paper, we push the boundaries of 4D-STEM in SEM and extend its capabilities in three key aspects: (1) faster acquisition rate with reduced data size, (2) higher angular resolution, and (3) application to various materials including conventional alloys and focused ion beam (FIB) lamella. Specifically, operating the MiniPIX Timepix3 detector in the event-driven mode significantly improves the acquisition rate by a factor of a few tenths compared to conventional frame-based mode, thereby opening up possibilities for integrating 4D-STEM into various <em>in situ</em> SEM testing. Furthermore, with a novel stage-detector geometry, a camera length of 160 mm is achieved which improves the angular resolution amplifying its utility, for example, magnetic or electric field imaging. Lastly, we successfully imaged a nanostructured platinum-copper thin film with a grain size of 16 nm and a thickness of 20 nm, and identified annealing twins in FIB-prepared polycrystalline copper using virtual dark-field imaging and orientation mapping. This work demonstrates the potential of synergetic combination of 4D-STEM with <em>in situ</em> experiments, and broadening its applications across a wide range of materials.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"276 ","pages":"Article 114203"},"PeriodicalIF":2.1,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580153","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}

引用次数: 0

Cryogen-free low-temperature photoemission electron microscopy for high-resolution nondestructive imaging of electronic phases 用于电子相高分辨率无损成像的无低温光电发射电子显微镜

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-07-01 DOI: 10.1016/j.ultramic.2025.114204

Chen Wang , Shaoshan Wang , Chuan Guo , Chengjian Yu , Qi Fu , Xiaopeng Xie , Changxi Zheng

{"title":"Cryogen-free low-temperature photoemission electron microscopy for high-resolution nondestructive imaging of electronic phases","authors":"Chen Wang , Shaoshan Wang , Chuan Guo , Chengjian Yu , Qi Fu , Xiaopeng Xie , Changxi Zheng","doi":"10.1016/j.ultramic.2025.114204","DOIUrl":"10.1016/j.ultramic.2025.114204","url":null,"abstract":"<div><div>Quantum materials exhibit phases such as superconductivity at low temperatures, yet imaging their phase transition dynamics with high spatial resolution remains challenging due to conventional tools' limitations—scanning tunneling microscopy offers static snapshots, while transmission electron microscopy lacks band sensitivity. Photoemission electron microscopy (PEEM) can resolve band structures in real/reciprocal spaces rapidly, but suffering from insufficient resolution for (near)atomic-scale quantum physics due to the unstable cooling designs. Here, we developed cryogen-free low-temperature PEEM (CFLT-PEEM) achieving 21.1 K stably. CFLT-PEEM attains a record-breaking resolution of 4.48 nm without aberration correction, enabling direct visualization of surface-state distribution characteristics along individual atomic steps. The advancement lies in narrowing the segment of band structures for imaging down to 160 meV, which minimizes the chromatic aberration of PEEM. CFLT-PEEM enables rapid, nondestructive high-resolution imaging of cryogenic electronic structures, positioning it as a powerful tool for physics and beyond.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"277 ","pages":"Article 114204"},"PeriodicalIF":2.1,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614592","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}

引用次数: 0

EstimateNoiseSEM: A novel framework for deep learning based noise estimation of scanning electron microscopy images EstimateNoiseSEM：一种基于深度学习的扫描电镜图像噪声估计新框架

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-06-28 DOI: 10.1016/j.ultramic.2025.114192

Sheikh Shah Mohammad Motiur Rahman , Michel Salomon , Sounkalo Dembélé

{"title":"EstimateNoiseSEM: A novel framework for deep learning based noise estimation of scanning electron microscopy images","authors":"Sheikh Shah Mohammad Motiur Rahman , Michel Salomon , Sounkalo Dembélé","doi":"10.1016/j.ultramic.2025.114192","DOIUrl":"10.1016/j.ultramic.2025.114192","url":null,"abstract":"<div><div>This paper introduces a framework (EstimateNoiseSEM) to automate noise estimation in scanning electron microscopy (SEM) images. Within this framework, a classification network selection mechanism facilitates the choice of a more optimized classification approach. Consequently, the classification stage determines the image’s noise type, while the regression model predicts the corresponding noise level. Noise estimation, which includes the noise type and level, is necessary to perform denoising in most cases. This study targeted the noise in scanning electron microscopy (SEM) images. Indeed, depending on the dwell time, the SEM produces different types of noise (Gaussian or Gamma) that can pose uncertainty problems during denoising. That is why, the multi-stage scheme based on deep learning was proposed in this study. The proposed approach performed better in Gaussian noise classification with more than 80% Accuracy, Precision, Recall, and F1-score on synthetic noisy samples and 0.98+/-0.01 root squared error in Gaussian noise classification. The classification network once achieved 97% of accuracy for Gaussian noise classification which decreased to 80% later on because of the uncertainty of Gamma noise levels. However, this study also provides detailed insights into the Gamma noise estimation process. These insights may guide us or the community in developing deep learning-based Gamma noise estimation techniques.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"276 ","pages":"Article 114192"},"PeriodicalIF":2.1,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518010","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}

引用次数: 0

Differences between differential phase contrast and electron holographic measurements of a GaN p-n junction GaN p-n结差相衬和电子全息测量的差异

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-06-21 DOI: 10.1016/j.ultramic.2025.114191

Laura Niermann

{"title":"Differences between differential phase contrast and electron holographic measurements of a GaN p-n junction","authors":"Laura Niermann","doi":"10.1016/j.ultramic.2025.114191","DOIUrl":"10.1016/j.ultramic.2025.114191","url":null,"abstract":"<div><div>Modern semiconductor devices require control of the electrostatic potential landscape at nanometer scale, which is especially important for materials like the Group III-Nitrides, where polarization effects cause additional sheet charges at interfaces. In this work two complementary electron microscopic methods, differential phase contrast (DPC) and electron holography (EH), are used for characterization of a GaN p–n junction in one and the same sample. In comparison, the values obtained for the junction’s characteristics, like the built-in potential step, the maximum fields strength, and the width of the space charge region, were significantly larger and also closer to the expected values, when measured by means of EH. A key difference in the measurements is the vastly lower illumination dose rates within the EH experiments. Therefore, the lower generation rate of electron–hole pairs might lead to a lower beam induced bias during the EH measurement. These findings demonstrate that in future experiments the impact of the electron illumination must be considered for accurate nanoscale electrostatic field and potential measurements.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"276 ","pages":"Article 114191"},"PeriodicalIF":2.1,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338804","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}

引用次数: 0

TEM-EDS microanalysis: Comparison between different electron sources, accelerating voltages and detection systems TEM-EDS微分析：不同电子源、加速电压和检测系统的比较

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-06-17 DOI: 10.1016/j.ultramic.2025.114201

Roberto Conconi , María del Mar Abad Ortega , Fernando Nieto , Paolo Buono , Giancarlo Capitani

{"title":"TEM-EDS microanalysis: Comparison between different electron sources, accelerating voltages and detection systems","authors":"Roberto Conconi , María del Mar Abad Ortega , Fernando Nieto , Paolo Buono , Giancarlo Capitani","doi":"10.1016/j.ultramic.2025.114201","DOIUrl":"10.1016/j.ultramic.2025.114201","url":null,"abstract":"<div><div>Two TEM-EDS quantification methods based on standards of known compositions, namely the Cliff and Lorimer approximation and the absorption correction method based on electroneutrality are employed and the results obtained with three different TEMs and EDS systems, compared. The three TEM instruments differ in source type (field emission vs. thermionic), accelerating voltage (200 vs. 300 kV) and EDS system type (4 in-column silicon drift detector (SDD) vs. single SDD). We found that EDS calibration appears to be “strictly instrument specific”, i.e., no universally valid <em>k</em>-factors can exist, but only <em>k</em>-factor sets for a specific combination of microscope and EDS system. As expected, 4-in column SDD systems, because of their larger sensitive areas compared to classical single SDD, are more efficient in data collection and, therefore, have lower detection limits. However, other sources of error may influence the final output, sometimes subverting the expectations. EDS analyses performed with FEG-TEMs exhibit lower radiation-induced migration of weakly bounded elements than TEMs equipped with a conventional source and lower beam current. This result may be explained by the smaller spot size used with the conventional TEM that in total led to a higher electron dose per sample atom. In addition, this work confirms that the absorption correction method is to be preferred whenever dealing with thick and/or dense samples, whereas the Cliff and Lorimer approximation, because simpler and faster, in all the other cases. Finally, we renew the necessity to determine two distinct <em>k<sub>O/Si</sub></em> factors, one for lighter and one for denser compounds.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"276 ","pages":"Article 114201"},"PeriodicalIF":2.1,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365802","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}

引用次数: 0

Improving the elemental and imaging accuracy in atom probe tomography of (Ti,Si)N single and multilayer coatings using isotopic substitution of N 用N同位素取代提高（Ti,Si）N单层和多层涂层原子探针层析成像的元素和成像精度

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-06-17 DOI: 10.1016/j.ultramic.2025.114200

Saeideh Naghdali , Maximilian Schiester , Helene Waldl , Velislava Terziyska , Marcus Hans , Daniel Primetzhofer , Nina Schalk , Michael Tkadletz

{"title":"Improving the elemental and imaging accuracy in atom probe tomography of (Ti,Si)N single and multilayer coatings using isotopic substitution of N","authors":"Saeideh Naghdali , Maximilian Schiester , Helene Waldl , Velislava Terziyska , Marcus Hans , Daniel Primetzhofer , Nina Schalk , Michael Tkadletz","doi":"10.1016/j.ultramic.2025.114200","DOIUrl":"10.1016/j.ultramic.2025.114200","url":null,"abstract":"<div><div>This study addresses the challenges in analyzing (Ti,Si)N coatings using atom probe tomography (APT). Overlapping mass-to-charge state ratios in APT mass spectra hinder unambiguous identification of Si and N, thus, isotopic substitution of naturally abundant nitrogen by <sup>15</sup>N-enriched nitrogen was applied to disentangle the mass-spectral overlaps. A series of model coatings, namely, Ti-N, Si-N, and Ti-Si-N single layer coatings were utilized to investigate elemental accuracy, while their corresponding multilayer coatings were used to assess lateral resolution and imaging accuracy. The coatings were sputter-deposited using i) naturally abundant nitrogen and ii) <sup>15</sup>N-enriched nitrogen, respectively. Subsequently, the coatings were analyzed with a LEAP 5000 XR atom probe. Accuracy in obtained concentrations was cross-validated with elastic recoil detection analysis (ERDA) combined with Rutherford backscattering spectrometry (RBS). The investigation showed that isotopic substitution allows to differentiate the Si and N peaks in the mass spectra and significantly reduces compositional discrepancies between APT and ERDA/RBS results. Despite remaining minor peak overlaps, which can result in inaccuracies in determining the elemental composition, isotopic substitution has proven to be an effective method for peak differentiation and correcting the obtained elemental composition of Ti-Si-N. Moreover, isotopic substitution can predominantly increase the elemental accuracy and imaging accuracy of APT measurements of multilayer coatings.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"276 ","pages":"Article 114200"},"PeriodicalIF":2.1,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365801","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}

引用次数: 0

Can low energy (1–20 eV) electron microscopy produce damage-free images of biological samples? 低能量（1-20 eV）电子显微镜能产生无损伤的生物样品图像吗？

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-06-16 DOI: 10.1016/j.ultramic.2025.114197

Yi Zheng, Léon Sanche

{"title":"Can low energy (1–20 eV) electron microscopy produce damage-free images of biological samples?","authors":"Yi Zheng, Léon Sanche","doi":"10.1016/j.ultramic.2025.114197","DOIUrl":"10.1016/j.ultramic.2025.114197","url":null,"abstract":"<div><div>Electron microscopy constitutes an efficient and well-established method to visualize biological material on the nanoscale. The image is usually produced by a high energy electron beam, which can damage the biological sample. To reduce image degradation, Neu et al. [Ultramicroscopy 222 (2021) 113,199] recently suggested the possibility of damage-free imaging of such samples at nm resolution using as a probe low energy electron (LEEs). The aims of the present article are to 1) present a simple and short description of LEE inelastic scattering and attachment in molecular solids in the 0–20 eV range, 2) show that principally due to the formation of transient anions (TAs) in biological material, by temporary LEE attachment to molecular sites, damage-free electron microscopy may be difficult to achieve and 3) suggest specimen conditions that reduce the damage produced by TAs to inflict minimum damage to biological samples in LEE microscopy. We provide examples of lesions induced by electrons of energies below 3 eV in short DNA strands composed of 16 base-pair oligonucleotides and on the 1–20 eV dependence of effective damage yields from LEE-bombarded plasmid DNA. The damaged samples were produced from 5-monolayer films lyophilized on tantalum substrates and transferred to ultra-high vacuum to be bombarded with LEEs. The products were identified and quantified ex-vacuo by LC-MS-MS and electrophoresis, respectively. Such effective yields, and the corresponding absolute cross sections derived from model analysis, should allow estimating beam damage and image quality in the visualization of thin biological films by LEE microscopy.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"276 ","pages":"Article 114197"},"PeriodicalIF":2.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144307813","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}

引用次数: 0

Valence EELS study of the composition of a liquid phase in a Janus Sn-Ge nanoparticle over a temperature range of 250–750 °C 在250-750℃的温度范围内，对Janus Sn-Ge纳米颗粒液相组成的价态EELS研究

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-06-16 DOI: 10.1016/j.ultramic.2025.114199

Olha Khshanovska, Aleksandr Kryshtal

{"title":"Valence EELS study of the composition of a liquid phase in a Janus Sn-Ge nanoparticle over a temperature range of 250–750 °C","authors":"Olha Khshanovska, Aleksandr Kryshtal","doi":"10.1016/j.ultramic.2025.114199","DOIUrl":"10.1016/j.ultramic.2025.114199","url":null,"abstract":"<div><div>Mapping the composition of liquid alloy nanoparticles in TEM at relatively low electron doses is essential for emerging nanotechnologies. In this work, we used volume and surface plasmon energies to determine the composition across different regions of a single Sn-Ge nanoparticle over a temperature range of 250–750 °C. A 53 nm Janus nanoparticle, composed of liquid Sn and solid Ge sides, was heated in a TEM, inducing the gradual dissolution of Ge into liquid Sn. Low-loss electron energy loss spectral images were acquired at 50 °C intervals, and plasmon energies were accurately measured using model-based fitting.</div><div>We demonstrated that the free-electron gas Drude model, combined with Zen’s law of alloy volume-concentration relation, enables the reliable determination of the composition of liquid Sn-Ge alloy from both surface and volume plasmon energy shifts. The determined compositions of the liquid alloy were consistent with EDX measurements and the liquidus line of the phase diagram. A homogeneous distribution of chemical elements in the liquid Sn-Ge alloy was revealed. At the same time, the composition on the Ge side of the nanoparticle was inhomogeneous, indicating the formation of a thin liquid shell over the solid Ge core. As a result, Ge in the Sn-Ge Janus nanoparticle exhibited highly tunable surface plasmon resonance, with its energy varying between 10.75 and 9.25 eV over a temperature range of 250–750 °C.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"276 ","pages":"Article 114199"},"PeriodicalIF":2.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365803","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}

引用次数: 0