Ultramicroscopy最新文献

{"title":"Interpretability of high-resolution transmission electron microscopy images","authors":"William Bang Lomholdt ,&nbsp;Matthew Helmi Leth Larsen ,&nbsp;Cuauhtemoc Nuñez Valencia ,&nbsp;Jakob Schiøtz ,&nbsp;Thomas Willum Hansen","doi":"10.1016/j.ultramic.2024.113997","DOIUrl":"10.1016/j.ultramic.2024.113997","url":null,"abstract":"<div><p>High-resolution electron microscopy is a well-suited tool for characterizing the nanoscale structure of materials. However, the interaction of the sample and the high-energy electrons of the beam can often have a detrimental impact on the sample structure. This effect can only be alleviated by decreasing the number of electrons to which the sample is exposed but will come at the cost of a decreased signal-to-noise ratio in the resulting image. Images with low signal to noise ratios are often challenging to interpret as parts of the sample with a low interaction with the electron beam are reproduced with very low contrast. Here we suggest simple measures as alternatives to the conventional signal-to-noise ratio and investigate how these can be used to predict the interpretability of the electron microscopy images. We test the models on a sample consisting of gold nanoparticles supported on a cerium dioxide substrate. The models are evaluated based on series of images acquired at varying electron dose.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"263 ","pages":"Article 113997"},"PeriodicalIF":2.2,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000767/pdfft?md5=984e6740155e565050b5a2415524a89c&pid=1-s2.0-S0304399124000767-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141184736","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}

{"title":"Reaction-diffusion study of electron-beam-induced contamination growth","authors":"Erich Müller ,&nbsp;Katharina Adrion ,&nbsp;Milena Hugenschmidt ,&nbsp;Dagmar Gerthsen","doi":"10.1016/j.ultramic.2024.113995","DOIUrl":"10.1016/j.ultramic.2024.113995","url":null,"abstract":"<div><p>A time-dependent reaction-diffusion model was elaborated to better understand the dynamical growth of contamination on surfaces illuminated by an electron beam. The goal of this work was to fully describe the flow of hydrocarbon molecules, denoted as contaminants, and their polymerization in the irradiated area with the number of parameters reduced to a minimum necessary. It was considered that the diffusion process of contaminants is driven by the gradient of their surface density generated by the impact of a circular homogeneous electron beam. The contribution of the residual gas atmosphere in the instrument was described by the tendency to reestablish the initial equilibrium surface density of contaminants before irradiation. The four unknown parameters of the model, the electron interaction cross-section, the diffusion coefficient, the initial surface density of contaminants, and the frequency of the supply of contaminants from the residual gas atmosphere were determined by comparing the modeled contamination growth with experimental results. The experiments were designed such that the influence of the single parameters could be unequivocally separated. To follow the dynamical evolution of the system and to generate time-resolved distinct experimental data, successive contamination measurements were performed at short time intervals up to 20 min. The local height and shape of the grown contamination were quantified by evaluating high-angle annular dark-field (HAADF) scanning-transmission- electron-microcopy (STEM) image intensities and corresponding Monte-Carlo simulations. Our model also applies to nonhomogeneous initial conditions like the reduced local surface density of contaminants after previous beam-showering. The dynamic analyses of this process might provide hints regarding the relative size of the contaminant molecules and also indicate some measures for the reduction of contamination growth.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"264 ","pages":"Article 113995"},"PeriodicalIF":2.2,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000743/pdfft?md5=b52e487c25a3a15e9b96b35b77c28a8c&pid=1-s2.0-S0304399124000743-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141293738","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}

{"title":"Direct investigations of interactions between nucleolins and aptamers on pancreatic cancer and normal cells by atomic force microscopy","authors":"Xinyu Li ,&nbsp;Longyun Chen ,&nbsp;Sudong Kong ,&nbsp;Haijian Zhong ,&nbsp;Feng Jiang ,&nbsp;Weidong Zhao","doi":"10.1016/j.ultramic.2024.113986","DOIUrl":"10.1016/j.ultramic.2024.113986","url":null,"abstract":"<div><p>Nucleolin is overexpressed on the surface of pancreatic cancer cells and are regarded as the remarkable therapeutic target. Aptamers are capable of binding the external domain of nucleolin on the cell surface with high affinity and specificity. But nucleolin has not been localized on pancreatic cancer cells at very high spatial resolution, and the interactions between nucleolin and aptamers have not been investigated at very high force resolution level. In this work, nucleolin was localized on pancreatic cancer and normal cells by aptamers (9FU-AS1411-NH₂, AS1411-NH₂ and CRO<img>NH₂) in Single Molecule Recognition Imaging mode of Atomic Force Microscopy. There are plenty of nucleolin on the surfaces of pancreatic cancer cells (area percentage about 5 %), while there are little nucleolin on the surfaces of normal cells. The interactions between three types of aptamers and nucleolins on the surfaces of pancreatic cancer cells were investigated by Single Molecule Force Spectroscopy. The unbinding forces of nucleolins-(9FU-AS1411-NH₂) are larger than nucleolins-(AS1411-NH₂). The dissociation activation energy on nucleolin-(9FU-AS1411-NH₂) is higher than nucleolin-(AS1411-NH₂), which indicates that the former complex is more stable and harder to dissociate than the later complex. There are no unbinding forces between nucleolin and CRO<img>NH₂. All these demonstrate that nucleolin was localized on pancreatic cancer and normal cells at single molecule level quantitatively, and the interactions (unbinding forces and kinetics) between nucleolin and aptamers were studied at picoNewton level. The approaches and results of this work will pave new ways in the investigations of nucleolin and aptamers, and will also be useful in the studies on other proteins and their corresponding aptamers.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"263 ","pages":"Article 113986"},"PeriodicalIF":2.2,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141065776","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}

{"title":"Fourier transform-based post-processing drift compensation and calibration method for scanning probe microscopy","authors":"M. Le Ster,&nbsp;S. Pawłowski,&nbsp;I. Lutsyk,&nbsp;P.J. Kowalczyk","doi":"10.1016/j.ultramic.2024.113984","DOIUrl":"https://doi.org/10.1016/j.ultramic.2024.113984","url":null,"abstract":"<div><p>Scanning probe microscopy (SPM) is ubiquitous in nanoscale science allowing the observation of features in real space down to the angstrom resolution. The scanning nature of SPM, wherein a sharp tip rasters the surface during which a physical setpoint is maintained via a control feedback loop, often implies that the image is subject to drift effects, leading to distortion of the resulting image. While there are <em>in-operando</em> methods to compensate for the drift, correcting the residual linear drift in obtained images is often neglected. In this paper, we present a reciprocal space-based technique to compensate the linear drift in atomically-resolved scanning probe microscopy images without distinction of the fast and slow scanning directions; furthermore this method does not require the set of SPM images obtained for the different scanning directions. Instead, the compensation is made possible by the a priori knowledge of the lattice parameters. The method can also be used to characterize and calibrate the SPM instrument.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"263 ","pages":"Article 113984"},"PeriodicalIF":2.2,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000639/pdfft?md5=d7b623a058150a9edba27b104bf57fbf&pid=1-s2.0-S0304399124000639-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140918485","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}

{"title":"A novel STM for quality atomic resolution with piezoelectric motor of high compactness and simplicity","authors":"Muhammad Touqeer ,&nbsp;Behnam Esmaeilzadeh ,&nbsp;Wenjie Meng ,&nbsp;Jihao Wang ,&nbsp;Syed Asad Maqbool ,&nbsp;Shaofeng Zheng ,&nbsp;Liu Junwei ,&nbsp;Yubin Hou ,&nbsp;Qingyou Lu","doi":"10.1016/j.ultramic.2024.113983","DOIUrl":"10.1016/j.ultramic.2024.113983","url":null,"abstract":"<div><p>Scanning tunneling microscope (STM) is a renowned scientific tool for obtaining high-resolution atomic images of materials. Herein, we present an innovative design of the scanning unit with a compact yet powerful inertial piezoelectric motor inspired by the Spider Drive motor principle. The scanning unit mainly consists of a small 9 mm long piezoelectric tube scanner (PTS), one end of which is coaxially connected to the main sapphire body of the STM. Of particular emphasis in this design is the piezoelectric shaft (PS), constructed from piezoelectric material instead of conventional metallic or zirconium materials. The PS is a rectangular piezoelectric stack composed of two piezoelectric plates, which are elastically clamped on the inner wall of the PTS via a spring strip. The PTS and PS expand and contract independently with each other to improve the inertial force and reduce the threshold voltage. To ensure the stability of the PS and balance the stepping performance of the inertial motor, a counterweight, and a matching conical spring are fixed at the tail of the PS. This innovative design allows for the assessment of scanning unit performance by applying a driving signal, threshold voltage is 50 V at room temperature. Step sizes vary from 0.1 to 1 µm by changing the driving signal at room temperature. Furthermore, we successfully obtained atomic-resolution images of a highly oriented pyrolytic graphite (HOPG) sample and low drift rates of 23.4 pm/min and 34.6 pm/min in X-Y plane and Z direction, respectively, under ambient conditions. This small, compact STM unit has the potential for the development of a rotatable STM for use in cryogen-free magnets, and superconducting magnets.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"263 ","pages":"Article 113983"},"PeriodicalIF":2.2,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140946052","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}

{"title":"Atomic force microscopy in mechanical measurements of single nanowires","authors":"Bartosz C. Pruchnik ,&nbsp;Janusz D. Fidelus ,&nbsp;Ewelina Gacka ,&nbsp;Krystyna Mika ,&nbsp;Leszek Zaraska ,&nbsp;Grzegorz D. Sulka ,&nbsp;Teodor P. Gotszalk","doi":"10.1016/j.ultramic.2024.113985","DOIUrl":"https://doi.org/10.1016/j.ultramic.2024.113985","url":null,"abstract":"<div><p>In this paper, we present the results of mechanical measurement of single nanowires (NWs) in a repeatable manner. Substrates with specifically designed mechanical features were used for NW placement and localization for measurements of properties such as Young's modulus or tensile strength of NW with an atomic force microscopy (AFM) system. Dense arrays of zinc oxide (ZnO) nanowires were obtained by one-step anodic oxidation of metallic Zn foil in a sodium bicarbonate electrolyte and thermal post-treatment. ZnO NWs with a hexagonal wurtzite structure were fixed to the substrates using focused electron beam-induced deposition (FEBID) and were annealed at different temperatures <em>in situ</em>. We show a 10-fold change in the properties of annealed materials as well as a difference in the properties of the NW materials from their bulk values with pre-annealed Young modulus at the level of 20 GPa and annealed reaching 200 GPa. We found the newly developed method to be much more versatile, allowing for <em>in situ</em> operations of NWs, including measurements with different methods of scanning probe microscopy.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"263 ","pages":"Article 113985"},"PeriodicalIF":2.2,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140950198","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}

{"title":"Systematic study of FIB-induced damage for the high-quality TEM sample preparation","authors":"Jun Uzuhashi,&nbsp;Tadakatsu Ohkubo","doi":"10.1016/j.ultramic.2024.113980","DOIUrl":"https://doi.org/10.1016/j.ultramic.2024.113980","url":null,"abstract":"<div><p>Nowadays, a focused Ga ion beam (FIB) with a scanning electron microscopy (SEM) system has been widely used to prepare the thin-foil sample for transmission electron microscopy (TEM) or scanning TEM (STEM) observation. An establishment of a solid strategy for a reproducible high-quality sample preparation process is essential to carry out high-quality (S)TEM analysis. In this work, the FIB damages introduced by Ga⁺ beam were investigated both experimentally and stopping and range of ions in matter (SRIM) simulation for silicon (Si), gallium nitride (GaN), indium phosphide (InP), and gallium arsenide (GaAs) semiconductors. It has been revealed that experimental investigations of the FIB-induced damage are in good agreement with SRIM simulation by defining the damage as not only “amorphization” but also “crystal distortion”. The systematic evaluation of FIB damages shown in this paper should be indispensable guidance for reliable (S)TEM sample preparation.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"262 ","pages":"Article 113980"},"PeriodicalIF":2.2,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140822817","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}

{"title":"Non-negative matrix factorization-aided phase unmixing and trace element quantification of STEM-EDXS data","authors":"Hui Chen ,&nbsp;Farhang Nabiei ,&nbsp;James Badro ,&nbsp;Duncan T.L. Alexander ,&nbsp;Cécile Hébert","doi":"10.1016/j.ultramic.2024.113981","DOIUrl":"10.1016/j.ultramic.2024.113981","url":null,"abstract":"<div><p>Energy-dispersive X-ray spectroscopy (EDXS) mapping with a scanning transmission electron microscope (STEM) is commonly used for chemical characterization of materials. However, STEM-EDXS quantification becomes challenging when the phases constituting the sample under investigation share common elements and overlap spatially. In this paper, we present a methodology to identify, segment, and unmix phases with a substantial spectral and spatial overlap in a semi-automated fashion through combining non-negative matrix factorization with <em>a priori</em> knowledge of the sample. We illustrate the methodology using a sample taken from an electron beam-sensitive mineral assemblage representing Earth's deep mantle. With it, we retrieve the true EDX spectra of the constituent phases and their corresponding phase abundance maps. It further enables us to achieve a reliable quantification for trace elements having concentration levels of ∼100 ppm. Our approach can be adapted to aid the analysis of many materials systems that produce STEM-EDXS datasets having phase overlap and/or limited signal-to-noise ratio (SNR) in spatially-integrated spectra.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"263 ","pages":"Article 113981"},"PeriodicalIF":2.2,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000603/pdfft?md5=97084e4c961f6d0ff48c3721260748f3&pid=1-s2.0-S0304399124000603-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141162641","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}

{"title":"Standardization and quantification of backscattered electron imaging in scanning electron microscopy","authors":"Shih-Ming Wang ,&nbsp;Yu-Cheng Chiu ,&nbsp;Yu-Hsin Wu ,&nbsp;Bo-Yi Chen ,&nbsp;I-Ling Chang ,&nbsp;Chih-Wei Chang","doi":"10.1016/j.ultramic.2024.113982","DOIUrl":"https://doi.org/10.1016/j.ultramic.2024.113982","url":null,"abstract":"<div><p>Backscattered electron (BSE) imaging based on scanning electron microscopy (SEM) has been widely used in scientific and industrial disciplines. However, achieving consistent standards and precise quantification in BSE images has proven to be a long-standing challenge. Previous methods incorporating dedicated calibration processes and Monte Carlo simulations have still posed practical limitations for widespread adoption. Here we introduce a bolometer platform that directly measures the absorbed thermal energy of the sample and demonstrates that it can help to analyze the atomic number (<em>Z</em>) of the investigated samples. The technique, named Atomic Number Electron Microscopy (ZEM), employs the conservation of energy as the foundation of standardization and can serve as a nearly ideal BSE detector. Our approach combines the strengths of both BSE and ZEM detectors, simplifying quantitative analysis for samples of various shapes and sizes. The complementary relation between the ZEM and BSE signals also makes the detection of light elements or compounds more accessible than existing microanalysis techniques.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"262 ","pages":"Article 113982"},"PeriodicalIF":2.2,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140816151","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}

{"title":"Magnetic domain wall dynamics studied by in-situ lorentz microscopy with aid of custom-made Hall-effect sensor holder","authors":"Mari Honkanen ,&nbsp;Henri Lukinmaa ,&nbsp;Sami Kaappa ,&nbsp;Suvi Santa-aho ,&nbsp;Jaakko Kajan ,&nbsp;Samuli Savolainen ,&nbsp;Lucio Azzari ,&nbsp;Lasse Laurson ,&nbsp;Mikko Palosaari ,&nbsp;Minnamari Vippola","doi":"10.1016/j.ultramic.2024.113979","DOIUrl":"https://doi.org/10.1016/j.ultramic.2024.113979","url":null,"abstract":"<div><p>We built a custom-made holder with a Hall-effect sensor to measure the single point magnetic flux density inside a transmission electron microscope (TEM, JEM-F200, JEOL). The measurement point is at the same place as the sample inside the TEM. We utilized information collected with the Hall-effect sensor holder to study magnetic domain wall (DW) dynamics by <em>in-situ</em> Lorentz microscopy. We generated an external magnetic field to the sample using the objective lens (OL) of the TEM. Based on our measurements with the Hall-effect sensor holder, the OL has nearly linear response, and when it is switched off, the strength of the magnetic field in the sample region is very close to 0 mT.</p><p>A ferritic-pearlitic sample studied has globular and lamellar cementite (Fe₃C) carbides in the ferrite matrix. Based on the <em>in-situ</em> Lorentz microscopy experiments, DWs in the ferritic matrix perpendicular to the lamellar carbides start to move first at ∼10 mT. At 160 mT, DWs inside the globular carbide start to disappear, and the saturation occurs at ∼210 mT. At 288 mT, the DWs parallel to the lamellar carbides still exist. Thus, these lamellar carbides are very strong pinning sites for DWs. We also run dynamical micromagnetic simulations to reproduce the DW disappearance in the globular carbide. As in the <em>in-situ</em> experiments, the DWs stay stable until the external field reaches the magnitude of 160 mT, and the DWs disappear before the field is 214 mT. In general, the micromagnetic simulations supported very well the interpretation of the experimental findings.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"262 ","pages":"Article 113979"},"PeriodicalIF":2.2,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000585/pdfft?md5=83afb159438d4d13ebbbcee41c7d1bf4&pid=1-s2.0-S0304399124000585-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140822818","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}