Ultramicroscopy最新文献_第8页

Optimization of three-dimensional electron diffuse scattering data acquisition 优化三维电子漫散射数据采集。

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2024-08-02 DOI: 10.1016/j.ultramic.2024.114023

Romy Poppe, Joke Hadermann

引用次数: 0

Probing the interaction range of electron beam-induced etching in STEM by a non-contact electron beam 用非接触电子束探测 STEM 中电子束诱导蚀刻的相互作用范围

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2024-07-25 DOI: 10.1016/j.ultramic.2024.114019

Stefan Manuel Noisternig , Christian Rentenberger , Christoph Gammer , H. Peter Karnthaler , Jani Kotakoski

{"title":"Probing the interaction range of electron beam-induced etching in STEM by a non-contact electron beam","authors":"Stefan Manuel Noisternig , Christian Rentenberger , Christoph Gammer , H. Peter Karnthaler , Jani Kotakoski","doi":"10.1016/j.ultramic.2024.114019","DOIUrl":"10.1016/j.ultramic.2024.114019","url":null,"abstract":"<div><p>Beside its main purpose as a high-end tool in material analysis reaching the atomic scale for structure, chemical and electronic properties, aberration-corrected scanning transmission electron microscopy (STEM) is increasingly used as a tool to manipulate materials down to that very same scale. In order to obtain exact and reproducible results, it is essential to consider the interaction processes and interaction ranges between the electron beam and the involved materials. Here, we show in situ that electron beam-induced etching in a low-pressure oxygen atmosphere can extend up to a distance of several nm away from the Ångström-size electron beam, usually used for probing the sample. This relatively long-range interaction is related to beam tails and inelastic scattering involved in the etching process. To suppress the influence of surface diffusion, we measure the etching effect indirectly on isolated nm-sized holes in a 2 nm thin amorphous carbon foil that is commonly used as sample support in STEM. During our experiments, the electron beam is placed inside the nanoholes so that most electrons cannot directly participate in the etching process. We characterize the etching process from measuring etching rates at multiple nanoholes with different distances between the hole edge and the electron beam.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"265 ","pages":"Article 114019"},"PeriodicalIF":2.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000986/pdfft?md5=485b4dbb0b43d77ef1652630b9d48731&pid=1-s2.0-S0304399124000986-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141847185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigation of thermal effects of laser micromachining for APT and TEM specimen preparation: A modeling and experimental study 用于制备 APT 和 TEM 试样的激光微加工热效应研究：建模与实验研究

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2024-07-22 DOI: 10.1016/j.ultramic.2024.114009

Anup Sharma , Shuo Zhang , Jing Fu , Deepak Marla

{"title":"Investigation of thermal effects of laser micromachining for APT and TEM specimen preparation: A modeling and experimental study","authors":"Anup Sharma , Shuo Zhang , Jing Fu , Deepak Marla","doi":"10.1016/j.ultramic.2024.114009","DOIUrl":"10.1016/j.ultramic.2024.114009","url":null,"abstract":"<div><p>Laser micromachining can serve as a coarse machining step during sample preparation for high-resolution characterization methods leading to swift sample preparation. However, selecting the right laser parameters is crucial to minimize the heat-affected zone, which can potentially compromise the microstructure of the specimen. This study focuses on evaluating the size of heat-affected zone in laser annular milling, aiming to ascertain a minimal scan diameter that safeguards the inner region of micropillars against thermal damage. A computational model based on the finite element method was utilized to simulate the laser heating process. To validate the simulation results, a picosecond pulsed laser is then used to machine the micropillars of Al and Si. The laser-machined samples were subjected to surface and microstructural analysis using Scanning Electron Microscope (SEM) and Electron Backscatter Diffraction (EBSD) scans. The length of heat affected zone obtained from simulations was approximately 6 <span><math><mi>μ</mi></math></span>m for silicon and 12 <span><math><mi>μ</mi></math></span>m for aluminum. The diameter of micropillars formed with laser machining was 10 <span><math><mi>μ</mi></math></span>m for silicon 26 <span><math><mi>μ</mi></math></span>m for aluminum. The core of the pillars was preserved with less than one degree of microstructural misorientations making it suitable for further processing for preparing specimens for techniques like APT and TEM. For silicon micropillars, the preserved central region has a diameter of 6 <span><math><mi>μ</mi></math></span>m and for aluminum its around 20–24 <span><math><mi>μ</mi></math></span>m. Additionally, the study determines the minimum scan diameter that can be achieved using the given laser machining setup across a range of common materials.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"265 ","pages":"Article 114009"},"PeriodicalIF":2.1,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141736710","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

Characterization of structure and mixing in nanoparticle hetero-aggregates using convolutional neural networks: 3D-reconstruction versus 2D-projection 利用卷积神经网络表征纳米粒子异质聚集体的结构和混合情况：三维重建与二维投影

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2024-07-20 DOI: 10.1016/j.ultramic.2024.114020

Christoph Mahr , Jakob Stahl , Beeke Gerken , Florian F. Krause , Marco Schowalter , Tim Grieb , Lutz Mädler , Andreas Rosenauer

{"title":"Characterization of structure and mixing in nanoparticle hetero-aggregates using convolutional neural networks: 3D-reconstruction versus 2D-projection","authors":"Christoph Mahr , Jakob Stahl , Beeke Gerken , Florian F. Krause , Marco Schowalter , Tim Grieb , Lutz Mädler , Andreas Rosenauer","doi":"10.1016/j.ultramic.2024.114020","DOIUrl":"10.1016/j.ultramic.2024.114020","url":null,"abstract":"<div><p>Structural and chemical characterization of nanomaterials provides important information for understanding their functional properties. Nanomaterials with characteristic structure sizes in the nanometer range can be characterized by scanning transmission electron microscopy (STEM). In conventional STEM, two-dimensional (2D) projection images of the samples are acquired, information about the third dimension is lost. This drawback can be overcome by STEM tomography, where the three-dimensional (3D) structure is reconstructed from a series of projection images acquired using various projection directions. However, 3D measurements are expensive with respect to acquisition and evaluation time. Furthermore, the method is hardly applicable to beam-sensitive materials, i.e. samples that degrade under the electron beam. For this reason, it is desirable to know whether sufficient information on structural and chemical information can be extracted from 2D-projection measurements. In the present work, a comparison between 3D-reconstruction and 2D-projection characterization of structure and mixing in nanoparticle hetero-aggregates is provided. To this end, convolutional neural networks are trained in 2D and 3D to extract particle positions and material types from the simulated or experimental measurement. Results are used to evaluate structure, particle size distributions, hetero-aggregate compositions and mixing of particles quantitatively and to find an answer to the question, whether an expensive 3D characterization is required for this material system for future characterizations.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"265 ","pages":"Article 114020"},"PeriodicalIF":2.1,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000998/pdfft?md5=f158e30e11578d894c5ad319e0ff62f4&pid=1-s2.0-S0304399124000998-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141851250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Calibrating cryogenic temperature of TEM specimens using EELS 利用 EELS 标定 TEM 试样的低温温度

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2024-07-08 DOI: 10.1016/j.ultramic.2024.114008

Abinash Kumar , Elizaveta Tiukalova , Kartik Venkatraman, Andrew Lupini, Jordan A. Hachtel, Miaofang Chi

{"title":"Calibrating cryogenic temperature of TEM specimens using EELS","authors":"Abinash Kumar , Elizaveta Tiukalova , Kartik Venkatraman, Andrew Lupini, Jordan A. Hachtel, Miaofang Chi","doi":"10.1016/j.ultramic.2024.114008","DOIUrl":"10.1016/j.ultramic.2024.114008","url":null,"abstract":"<div><p>Cryogenic Scanning/Transmission Electron Microscopy has been established as a leading method to image sensitive biological samples and is now becoming a powerful tool to understand materials' behavior at low temperatures. However, achieving precise local temperature calibration at low temperatures remains a challenge, which is especially crucial for studying phase transitions and emergent physical properties in quantum materials. In this study, we employ electron energy loss spectroscopy (EELS) to measure local cryogenic specimen temperatures. We use the temperature-dependent characteristics of aluminum's bulk plasmon peak in EEL spectra, which shifts due to changes in electron density caused by thermal expansion and contraction. We successfully demonstrate the versatility of this method by calibrating different liquid nitrogen cooling holders in various microscopes, regardless of whether a monochromated or non-monochromated electron beam is used. Temperature discrepancies between the actual temperature and the setpoint temperatures are identified across a range from room temperature to 100 K. This work demonstrates the importance of temperature calibrations at intermediate temperatures and presents a straightforward, robust method for calibrating local temperatures of cryogenically-cooled specimens in electron microscopes.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"265 ","pages":"Article 114008"},"PeriodicalIF":2.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141701765","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

Elastic strain mapping of plastically deformed materials by TEM 利用 TEM 绘制塑性变形材料的弹性应变图

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2024-07-07 DOI: 10.1016/j.ultramic.2024.114010

Arthur Després , Salomé Parent , Muriel Véron , Edgar F. Rauch , Anne Joulain , Hadi Bahsoun , Christophe Tromas

{"title":"Elastic strain mapping of plastically deformed materials by TEM","authors":"Arthur Després , Salomé Parent , Muriel Véron , Edgar F. Rauch , Anne Joulain , Hadi Bahsoun , Christophe Tromas","doi":"10.1016/j.ultramic.2024.114010","DOIUrl":"https://doi.org/10.1016/j.ultramic.2024.114010","url":null,"abstract":"<div><p>A method for mapping elastic strains by TEM in plastically deformed materials is presented. A characteristic feature of plastically deformed materials, which cannot be handled by standard strain measurement method, is the presence of orientation gradients. To circumvent this issue, we couple orientation and strain maps obtained from scanning precession electron diffraction datasets. More specifically, orientation gradients are taken into account by 1) identifying the diffraction spot positions in a reference pattern, 2) measuring the disorientation between the diffraction patterns in the map and the reference pattern, 3) rotating the coordinate system following the measured disorientation at each position in the map, 4) calculating strains in the rotated coordinate system. At present, only azimuthal rotations of the crystal are handled. The method is illustrated on a Cr<sub>2</sub>AlC monocrystal micropilar deformed in near simple flexion during a nanomechanical test. After plastic deformation, the sample contains dislocations arranged in pile-ups and walls. The strain-field around each dislocation is consistent with theory, and a clear difference is observed between the strain fields around pile-ups and walls. It is further remarked that strain maps allow for the orientation of the Burgers vector to be identified. Since the loading undergone by the sample is known, this also allows for the position of the dislocation sources to be estimated. Perspectives for the study of deformed materials are finally discussed.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"265 ","pages":"Article 114010"},"PeriodicalIF":2.1,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000895/pdfft?md5=aa6e2c1c7c0d811d16c0306cbb906d6f&pid=1-s2.0-S0304399124000895-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141594744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Robust methodology for the EBSD local misorientation analysis of surface cold work 表面冷加工 EBSD 局部错向分析的稳健方法学

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2024-06-27 DOI: 10.1016/j.ultramic.2024.114007

Ivan Bogachev , Kevin M. Knowles , Grant J. Gibson

{"title":"Robust methodology for the EBSD local misorientation analysis of surface cold work","authors":"Ivan Bogachev , Kevin M. Knowles , Grant J. Gibson","doi":"10.1016/j.ultramic.2024.114007","DOIUrl":"10.1016/j.ultramic.2024.114007","url":null,"abstract":"<div><p>The amount of cold work induced by a surface hardening technique and the depth to which it is produced within a metallic material are both important parameters within the field of surface engineering. In this paper a methodology of establishing reliable estimates of the depth and magnitude of cold work in surface hardened nickel-based superalloy single crystals from a dataset (map) of electron backscattered diffraction images through the analysis of local misorientations is described in detail. The impact of varying a number of acquisition parameters within the scanning electron microscope and the impact of the various post-acquisition analysis parameters on the outcome of the analysis are both described and discussed in detail. The Python script used to perform this analysis is published in full. The principles and processes underlying this methodology, as well as the published script, can be readily adapted for the analysis of datasets of electron backscattered diffraction images from other surface hardening techniques and other surface-hardened materials.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"266 ","pages":"Article 114007"},"PeriodicalIF":2.1,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S030439912400086X/pdfft?md5=a067032221c7c6a345e9c1eae3016ca7&pid=1-s2.0-S030439912400086X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141964464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Angular momentum transfer from swift electrons to non-spherical nanoparticles within the dipolar approximation 在双极近似条件下从快速电子到非球形纳米粒子的角动量传递

IF 2.2 3区工程技术

Ultramicroscopy Pub Date : 2024-06-11 DOI: 10.1016/j.ultramic.2024.114005

Jorge Luis Briseño-Gómez , Atzin López-Tercero , José Ángel Castellanos-Reyes , Alejandro Reyes-Coronado

{"title":"Angular momentum transfer from swift electrons to non-spherical nanoparticles within the dipolar approximation","authors":"Jorge Luis Briseño-Gómez , Atzin López-Tercero , José Ángel Castellanos-Reyes , Alejandro Reyes-Coronado","doi":"10.1016/j.ultramic.2024.114005","DOIUrl":"https://doi.org/10.1016/j.ultramic.2024.114005","url":null,"abstract":"<div><p>In this work, we study the angular momentum transfer from a single swift electron to non-spherical metallic nanoparticles, specifically investigating spheroidal and polyhedral (Platonic Solids) shapes. While previous research has predominantly focused on spherical nanoparticles, our work expands the knowledge by exploring various geometries. Employing classical electrodynamics and the small particle limit, we calculate the angular momentum transfer by integrating the spectral density, ensuring causality through Fourier-transform analysis. Our findings demonstrate that prolate spheroidal nanoparticles exhibit a single blueshifted plasmonic resonance, compared to spherical nanoparticles of equivalent volume, resulting in lower angular momentum transfer. Conversely, oblate nanoparticles display two resonances — one blueshifted and one redshifted — resulting in a higher angular momentum transfer than their spherical counterparts. Additionally, Platonic Solids with fewer faces exhibit significant redshifts in plasmonic resonances, leading to higher angular momentum transfer due to edge effects. We also observe resonances and angular momentum transfers with similar characteristics in specific pairs of Platonic Solids, known as duals. These results highlight promising applications, particularly in electron tweezers technology.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"264 ","pages":"Article 114005"},"PeriodicalIF":2.2,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000846/pdfft?md5=7e92976a208ff09f81d90142535741c9&pid=1-s2.0-S0304399124000846-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141428727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Origin of giant enhancement of phase contrast in electron holography of modulation-doped n-type GaN 调制掺杂 n 型氮化镓电子全息图中相位对比巨幅增强的起源

IF 2.2 3区工程技术

Ultramicroscopy Pub Date : 2024-06-09 DOI: 10.1016/j.ultramic.2024.114006

K. Ji , M. Schnedler , Q. Lan , J.-F. Carlin , R. Butté , N. Grandjean , R.E. Dunin-Borkowski , Ph. Ebert

{"title":"Origin of giant enhancement of phase contrast in electron holography of modulation-doped n-type GaN","authors":"K. Ji , M. Schnedler , Q. Lan , J.-F. Carlin , R. Butté , N. Grandjean , R.E. Dunin-Borkowski , Ph. Ebert","doi":"10.1016/j.ultramic.2024.114006","DOIUrl":"https://doi.org/10.1016/j.ultramic.2024.114006","url":null,"abstract":"<div><p>The electron optical phase contrast probed by electron holography at <span><math><mi>n</mi></math></span>-<span><math><msup><mrow><mi>n</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span> GaN doping steps is found to exhibit a giant enhancement, in sharp contrast to the always smaller than expected phase contrast reported for <span><math><mi>p</mi></math></span>-<span><math><mi>n</mi></math></span> junctions. We unravel the physical origin of the giant enhancement by combining off-axis electron holography data with self-consistent electrostatic potential calculations. The predominant contribution to the phase contrast is shown to arise from the doping dependent screening length of the surface Fermi-level pinning, which is induced by FIB-implanted carbon point defects below the outer amorphous shell. The contribution of the built-in potential is negligible for modulation doping and only relevant for large built-in potentials at e.g. <span><math><mi>p</mi></math></span>-<span><math><mi>n</mi></math></span> junctions. This work provides a quantitative approach to so-called dead layers at TEM lamellas.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"264 ","pages":"Article 114006"},"PeriodicalIF":2.2,"publicationDate":"2024-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000858/pdfft?md5=03c404a6f50a5b309404ae6f59a44c1b&pid=1-s2.0-S0304399124000858-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141324064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

New Poisson denoising method for pulse-count STEM imaging 用于脉冲计数 STEM 成像的泊松去噪新方法

IF 2.2 3区工程技术

Ultramicroscopy Pub Date : 2024-05-27 DOI: 10.1016/j.ultramic.2024.113996

Taichi Kusumi , Shun Katakami , Ryo Ishikawa , Kazuaki Kawahara , Tiarnan Mullarkey , Julie Marie Bekkevold , Jonathan J.P. Peters , Lewys Jones , Naoya Shibata , Masato Okada

引用次数: 0