Journal of microscopy最新文献

Quantifying phase magnitudes of open-source focused-probe 4D-STEM ptychography reconstructions.

IF 1.5 4区工程技术

Journal of microscopy Pub Date : 2025-03-29 DOI: 10.1111/jmi.13409

Toma Susi

{"title":"Quantifying phase magnitudes of open-source focused-probe 4D-STEM ptychography reconstructions.","authors":"Toma Susi","doi":"10.1111/jmi.13409","DOIUrl":"https://doi.org/10.1111/jmi.13409","url":null,"abstract":"Accurate computational ptychographic phase reconstructions are enabled by fast direct-electron cameras with high dynamic ranges used for four-dimensional scanning transmission electron microscopy (4D-STEM). The availability of open software packages is making such analyses widely accessible, and especially when implemented in Python, easy to compare in terms of computational efficiency and reconstruction quality. In this contribution, I reconstruct atomic phase shifts from convergent-beam electron diffraction maps of pristine monolayer graphene, which is an ideal dose-robust uniform phase object, acquired on a Dectris ARINA detector installed in a Nion UltraSTEM 100 operated at 60 keV with a focused-probe convergence semi-angle of 34 mrad. For two different recorded maximum scattering angle settings, I compare a range of direct and iterative open-source phase reconstruction algorithms, evaluating their computational efficiency and tolerance to reciprocal-space binning and real-space thinning of the data. The quality of the phase images is assessed by quantifying the variation of atomic phase shifts using a robust parameter-based method, revealing an overall agreement with some notable differences in the absolute magnitudes and the variation of the phases. Although such variation is not a major issue when analysing data with many identical atoms, it does put limits on what level of precision can be relied upon for unique sites such as defects or dopants, which also tend to be more dose-sensitive. Overall, these findings and the accompanying open data and code provide useful guidance for the sampling required for desired levels of phase precision, and suggest particular care is required when relying on electron ptychography for quantitative analyses of atomic-scale electromagnetic properties.","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143743239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Hard X-ray spectromicroscopy of Ni-rich cathodes under in situ liquid heating conditions.

IF 1.5 4区工程技术

Journal of microscopy Pub Date : 2025-03-26 DOI: 10.1111/jmi.13403

Gea T van de Kerkhof, Carmen Murphy, Shahul H Abdulrahman, Timothy Poon, Chris Hawkins, Mengliu Li, Angela E Goode, Julia E Parker, Manfred E Schuster

{"title":"Hard X-ray spectromicroscopy of Ni-rich cathodes under in situ liquid heating conditions.","authors":"Gea T van de Kerkhof, Carmen Murphy, Shahul H Abdulrahman, Timothy Poon, Chris Hawkins, Mengliu Li, Angela E Goode, Julia E Parker, Manfred E Schuster","doi":"10.1111/jmi.13403","DOIUrl":"https://doi.org/10.1111/jmi.13403","url":null,"abstract":"In situ microscopy involves imaging of samples under real reaction conditions. For electron microscopy, micro-electromechanical systems (MEMS) chips have previously been developed that can hold a liquid or gas inside the vacuum of the electron microscope, with electrical contacts that allow for heating or biasing of the sample. These chips have paved the way for high-resolution imaging of dynamic chemical reactions. Here, we report the use of such MEMS chips in an in-house developed setup for a hard X-ray nanoprobe, applied to Ni-rich cathode materials. We investigate the chemical and structural changes in nickel-rich cathodes upon exposure to electrolyte and under heating conditions using hard X-ray spectromicroscopy. As such, we find marked differences in the behaviour of pure LiNiO2 compared to Co and Mn substituted material, NMC811. The use of hard X-ray spectromicroscopy allows for imaging and observation of: (i) the oxidation state of nickel, changing from Ni3+ to Ni2+, (ii) the effect of a preexisting fracture in the sample and (iii) the structural degradation of the sample during accelerated aging.","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143709591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Optimized single-beam modulation argon ion milling for TEM cross-sectional specimens of nanostructured interfaces.

IF 1.5 4区工程技术

Journal of microscopy Pub Date : 2025-03-25 DOI: 10.1111/jmi.13406

Xiangtao Luo, Sujuan Ding, Haozhe Lu, Chuanhong Jin

{"title":"Optimized single-beam modulation argon ion milling for TEM cross-sectional specimens of nanostructured interfaces.","authors":"Xiangtao Luo, Sujuan Ding, Haozhe Lu, Chuanhong Jin","doi":"10.1111/jmi.13406","DOIUrl":"https://doi.org/10.1111/jmi.13406","url":null,"abstract":"High-quality transmission electron microscopy (TEM) specimens are critical for high-resolution imaging and conducting electron energy loss spectroscopy (EELS) analysis. However, fabricating cross-sectional TEM specimens with large, thin, and low-damage regions remains challenging, particularly with conventional mechanical polishing and Ar+ ion-beam milling methods. Here, we propose an optimised method based on Ar+ ion-beam milling that precisely maintains the consistency of the sample's thickness after mechanical polishing and fine-tunes Ar+ ion-beam milling parameters. Appropriately chosen milling parameters through real-time monitoring minimise the damaged layer's thickness, while optimised parameters reduce the redeposition of sputtered material. Applied to interfaces such as those between aligned carbon nanotube arrays (A-CNTs) and gate dielectrics key to next-generation nanoelectronics, we achieved samples with a 30 µm wide thin region, the thinnest area reaching 15 nm, preserving structural integrity and yielding a well-defined CNT-HfO2 interface. Notably, redeposition was reduced from 44.4% to 6.6%, and single-beam modulation enabled these extensive thin regions, outperforming dual-beam methods.","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143700561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Detecting charge transfer at defects in 2D materials with electron ptychography.

IF 1.5 4区工程技术

Journal of microscopy Pub Date : 2025-03-21 DOI: 10.1111/jmi.13404

Christoph Hofer, Jacob Madsen, Toma Susi, Timothy J Pennycook

{"title":"Detecting charge transfer at defects in 2D materials with electron ptychography.","authors":"Christoph Hofer, Jacob Madsen, Toma Susi, Timothy J Pennycook","doi":"10.1111/jmi.13404","DOIUrl":"https://doi.org/10.1111/jmi.13404","url":null,"abstract":"Electronic charge transfer at the atomic scale can reveal fundamental information about chemical bonding, but is far more challenging to directly image than the atomic structure. The charge density is dominated by the atomic nuclei, with bonding causing only a small perturbation. Thus detecting any change due to bonding requires a higher level of sensitivity than imaging structure and the overall charge density. Here we achieve the sensitivity required to detect charge transfer in both pristine and defected monolayer WS2 using the high dose efficiency of electron ptychography and its ability to correct for lens aberrations. Excellent agreement is achieved with first-principles image simulations including where thermal diffuse scattering is explicitly modelled via finite-temperature molecular dynamics based on density functional theory. The focused-probe ptychography configuration we use also provides the important ability to concurrently collect the annular dark-field signal, which can be unambiguously interpreted in terms of the atomic structure and chemical identity of the atoms, independently of the charge transfer. Our results demonstrate both the power of ptychographic reconstructions and the importance of quantitatively accurate simulations to aid their interpretation.","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143673415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Glass slide evanescent wave fluorescence biosensor integrated coupling aspherical lens with a sensing range of over 20 mm for multi-wavelength operation.

IF 1.5 4区工程技术

Journal of microscopy Pub Date : 2025-03-20 DOI: 10.1111/jmi.13405

Qun Dai, Yanjun Hu, Xingang Dai, Bowen Niu, Yuan Li, Guofang Fan

引用次数: 0

Model-based aberration corrected microscopy inside a glass tube.

IF 1.5 4区工程技术

Journal of microscopy Pub Date : 2025-03-16 DOI: 10.1111/jmi.13402

Daniël W S Cox, Tom Knop, Ivo M Vellekoop

引用次数: 0

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