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Krisper R, Lammer J, Pivak Y, Fisslthaler E, Grogger W. The Performance of EDXS at Elevated Sample Temperatures Using a MEMS-Based In Situ TEM Heating System. Ultramicroscopy 2022; 234:113461. [PMID: 35121282 DOI: 10.1016/j.ultramic.2021.113461] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 12/15/2021] [Accepted: 12/29/2021] [Indexed: 11/20/2022]
Abstract
Since the development of MEMS heating holders, dynamic in-situ experiments at elevated temperatures may be complemented by X-ray spectrometry for chemical analysis. Although the amount of IR radiation is small when compared to furnace holders, the influence of IR radiation emitted from the heating device on the quality of the X-ray spectra is significant. In this work, we systematically examine the influence of infrared (IR) radiation generated by MEMS-based in situ heating systems (DENSsolutions single- and double-tilt holders) on the results and interpretation of energy-dispersive X-ray (EDX) spectra through simulation and measurement. Focal points of interest in this study are the influence of holder geometry, shadowing and orientation with respect to the different emission characteristics of IR and X-ray photons and their interaction with a side-entry and a multi-detector system. IR photons substantially contribute to count rates, dead time, electronic noise levels, energy resolution, and detection efficiency of semiconductor detectors. At higher sample temperatures, they ultimately limit the feasibility of EDXS for elemental characterization and especially the traceability of low-Z elements. This work provides a quantitative insight into the influence of all relevant parameters related to in situ heating experiments on the spectral quality. Bearing this in mind, we aim to provide a guide to optimizing in situ heating experiments with respect to chemical EDXS analysis.
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Affiliation(s)
- Robert Krisper
- Graz Centre for Electron Microscopy (ZFE), Austrian Cooperative Research (ACR), Steyrergasse 17, 8010 Graz, Austria; Institute of Electron Microscopy and Nanoanalysis (FELMI), Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria.
| | - Judith Lammer
- Graz Centre for Electron Microscopy (ZFE), Austrian Cooperative Research (ACR), Steyrergasse 17, 8010 Graz, Austria; Institute of Electron Microscopy and Nanoanalysis (FELMI), Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
| | - Yevheniy Pivak
- DENSsolutions, Informaticalaan 12, Delft, 2628ZD, The Netherlands
| | - Evelin Fisslthaler
- Graz Centre for Electron Microscopy (ZFE), Austrian Cooperative Research (ACR), Steyrergasse 17, 8010 Graz, Austria
| | - Werner Grogger
- Graz Centre for Electron Microscopy (ZFE), Austrian Cooperative Research (ACR), Steyrergasse 17, 8010 Graz, Austria; Institute of Electron Microscopy and Nanoanalysis (FELMI), Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
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2
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The performance of analytical EMS and EDX systems, measured with a nickel oxide test specimen. ACTA ACUST UNITED AC 2020. [DOI: 10.1017/s0424820100139378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A test specimen consisting of a 50nm film of NiO on a 200-mesh molybdenum grid can be used to evaluate the diffraction, EELS and EDX capabilities of an analytical TEM. Several laboratories have utilised this specimen and their results have been compared. One measurement is the Mo-Kα/Ni-Kα ratio, which characterizes the amount of stray radiation within a TEM column; values are typically in the range 3 to 10 for conventional TEM's and as high as 40 for instruments in which beryllium sheet is used to shield the upper and lower polepieces; see Fig. 1. Another criterion is the peak/background ratio of the Ni-Kα peak, the background being measured within a lOeV window beneath the peak. This ratio reflects electronic noise as well as column radiation but correlates well with the Ni-Kα/Mo-Kα ratio (see Fig. 1), indicating that column radiation can substantially affect the EDX background.The variations in performance visible in Fig. 1 are partly due to differences in TEM accelerating voltage. Fig. 2 shows that higher peak/background is possible at higher voltage, as would expected if the background were entirely bremsstrahlung radiation.
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A Method to Characterize and Correct Elliptical Distortion in Electron Diffraction Patterns. ACTA ACUST UNITED AC 2018. [DOI: 10.1017/s1551929500059253] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
One of the main obstacles to performing electron crystallography analysis in a TEM is that the acquired electron diffraction data often exhibits some form of distortion introduced by the lens system. Recognizing this problem, Capitani et al. has proposed a method to detect such distortion, which is primarily elliptical, by using a single crystal standard. Once such elliptical distortion is characterized, electron diffraction data acquired later can then be corrected by means of image processing. However, it may be desirable to correct such distortion at the instrument level. In this article, a different approach to measuring diffraction elliptical distortion is proposed by characterizing diffraction ring patterns and it is demonstrated that by varying the objective lens stigmation settings, it is possible to eliminate this elliptical distortion completely.
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Numerical modeling of specimen geometry for quantitative energy dispersive X-ray spectroscopy. Ultramicroscopy 2018; 184:100-108. [DOI: 10.1016/j.ultramic.2017.08.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 08/21/2017] [Accepted: 08/29/2017] [Indexed: 11/16/2022]
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5
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Improvement of effective solid angle using virtual-pivot holder and large EDS detector. Micron 2016; 93:52-56. [PMID: 27923156 DOI: 10.1016/j.micron.2016.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/23/2016] [Accepted: 11/23/2016] [Indexed: 11/20/2022]
Abstract
This paper describes the effective solid angle improvement achieved using a large-area silicon drift detector together with a virtual-pivot double-tilt specimen holder. The virtual-pivot mechanism enables various designs of specimen-retaining and can reduce the shadowing effect. Energy-dispersive X-ray spectra were measured and converted into effective solid angles using different types of specimen holders and specimens. The investigated shadowing-free mechanical system yielded effective solid angles approaching the nominal solid angle of 0.464sr. In addition, we have demonstrated the availability of the plastic (polyetheretherketone) specimen holder for low system noise.
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Xu W, Dycus J, Sang X, LeBeau J. A numerical model for multiple detector energy dispersive X-ray spectroscopy in the transmission electron microscope. Ultramicroscopy 2016; 164:51-61. [DOI: 10.1016/j.ultramic.2016.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 02/13/2016] [Accepted: 02/18/2016] [Indexed: 10/22/2022]
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Mitchell DR, Nancarrow MJ. Probe current determination in analytical TEM/STEM and its application to the characterization of large area EDS detectors. Microsc Res Tech 2015; 78:886-93. [DOI: 10.1002/jemt.22551] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 07/05/2015] [Indexed: 11/09/2022]
Affiliation(s)
- David R.G. Mitchell
- Electron Microscopy Centre, Innovation Campus, University of Wollongong; Squires Way North Wollongong New South Wales 2500 Australia
| | - Mitchell J.B. Nancarrow
- Electron Microscopy Centre, Innovation Campus, University of Wollongong; Squires Way North Wollongong New South Wales 2500 Australia
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Mitchell DRG. Contamination mitigation strategies for scanning transmission electron microscopy. Micron 2015; 73:36-46. [PMID: 25885075 DOI: 10.1016/j.micron.2015.03.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/30/2015] [Accepted: 03/30/2015] [Indexed: 11/28/2022]
Abstract
Modern scanning transmission electron microscopy (STEM) enables imaging and microanalysis at very high magnification. In the case of aberration-corrected STEM, atomic resolution is readily achieved. However, the electron fluxes used may be up to three orders of magnitude greater than those typically employed in conventional STEM. Since specimen contamination often increases with electron flux, specimen cleanliness is a critical factor in obtaining meaningful data when carrying out high magnification STEM. A range of different specimen cleaning methods have been applied to a variety of specimen types. The contamination rate has been measured quantitatively to assess the effectiveness of cleaning. The methods studied include: baking, cooling, plasma cleaning, beam showering and UV/ozone exposure. Of the methods tested, beam showering is rapid, experimentally convenient and very effective on a wide range of specimens. Oxidative plasma cleaning is also very effective and can be applied to specimens on carbon support films, albeit with some care. For electron beam-sensitive materials, cooling may be the method of choice. In most cases, preliminary removal of the bulk of the contamination by methods such as baking or plasma cleaning, followed by beam showering, where necessary, can result in a contamination-free specimen suitable for extended atomic scale imaging and analysis.
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Affiliation(s)
- D R G Mitchell
- Electron Microscopy Centre, Australian Institute for Innovative Materials, Innovation Campus, University of Wollongong, North Wollongong, NSW 2500, Australia.
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Zaluzec NJ. Analytical formulae for calculation of X-ray detector solid angles in the scanning and scanning/transmission analytical electron microscope. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:1318-1326. [PMID: 24848939 DOI: 10.1017/s1431927614000956] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Closed form analytical equations used to calculate the collection solid angle of six common geometries of solid-state X-ray detectors in scanning and scanning/transmission analytical electron microscopy are presented. Using these formulae one can make realistic comparisons of the merits of the different detector geometries in modern electron column instruments. This work updates earlier formulations and adds new detector configurations.
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Affiliation(s)
- Nestor J Zaluzec
- Argonne National Laboratory,Electron Microscopy Center,Argonne,IL 60440,USA
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Watanabe M. Microscopy Hacks: development of various techniques to assist quantitative nanoanalysis and advanced electron microscopy. Microscopy (Oxf) 2013; 62:217-41. [DOI: 10.1093/jmicro/dfs085] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Armigliato A, Frabboni S, Gazzadi GC, Rosa R. FIB preparation of a NiO Wedge-Lamella and STEM X-ray microanalysis for the determination of the experimental k(O-Ni) Cliff-Lorimer coefficient. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19:79-84. [PMID: 23286220 DOI: 10.1017/s1431927612013876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A method for the fabrication of a wedge-shaped thin NiO lamella by focused ion beam is reported. The starting sample is an oxidized bulk single crystalline, <100> oriented, Ni commercial standard. The lamella is employed for the determination, by analytical electron microscopy at 200 kV of the experimental k(O-Ni) Cliff-Lorimer (G. Cliff & G.W. Lorimer, J Microsc 103, 203-207, 1975) coefficient, according to the extrapolation method by Van Cappellen (E. Van Cappellen, Microsc Microstruct Microanal 1, 1-22, 1990). The result thus obtained is compared to the theoretical k(O-Ni) values either implemented into the commercial software for X-ray microanalysis quantification of the scanning transmission electron microscopy/energy dispersive spectrometry equipment or calculated by the Monte Carlo method. Significant differences among the three values are found. This confirms that for a reliable quantification of binary alloys containing light elements, the choice of the Cliff-Lorimer coefficients is crucial and experimental values are recommended.
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12
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Enhanced Detection Sensitivity with a New Windowless XEDS System for AEM Based on Silicon Drift Detector Technology. ACTA ACUST UNITED AC 2010. [DOI: 10.1017/s1551929510000404] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
For many years now, the combination of the modern S/TEM system (scanning/transmission electron microscope) with the X-ray energy dispersive spectrometer (XEDS) has resulted in Analytical Electron Microscopes (AEMs) able to deliver both high-resolution imaging and elemental composition maps in the same instrument. This ability to correlate local elemental composition with microstructure has greatly broadened the applications realm of the S/TEM instrument. The boundaries of performance for many of these applications are now determined by limits in XEDS system detection sensitivity. In this article, we describe an AEM with greatly enhanced detection sensitivity due to a number of innovations in the system architecture, including: a high-brightness Schottky FEG source, four detectors integrated deeply into the objective lens, windowless silicon drift detector technology with shutters, and high-speed electronics readout. This new system architecture provides many performance benefits, such as improved light element detection, better sample tilt response, faster mapping, and especially enhanced system detection sensitivity.
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Armigliato A, Rosa R. X-ray microanalysis combined with monte carlo simulation for the analysis of layered thin films: the case of carbon contamination. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2009; 15:99-105. [PMID: 19284891 DOI: 10.1017/s1431927609090199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A previously developed Monte Carlo code has been extended to the X-ray microanalysis in a (scanning) transmission electron microscope of plan sections, consisting of bilayers and triple layers. To test the validity of this method for quantification purposes, a commercially available NiOx (x 1) thin film, deposited on a carbon layer, has been chosen. The composition and thickness of the NiO film and the thickness of the C support layer are obtained by fitting to the three X-ray intensity ratios I(NiK)/I(OK), I(NiK)/I(CK), and I(OK)/I(CK). Moreover, it has been investigated to what extent the resulting film composition is affected by the presence of a contaminating carbon film at the sample surface. To this end, the sample has been analyzed both in the (recommended) "grid downward" geometry and in the upside/down ("grid upward") situation. It is found that a carbon contaminating film of few tens of nanometers must be assumed in both cases, in addition to the C support film. Consequently, assuming the proper C/NiOx/C stack in the simulations, the Monte Carlo method yields the correct oxygen concentration and thickness of the NiOx film.
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Affiliation(s)
- Aldo Armigliato
- CNR-IMM, Sezione di Bologna, Via P. Gobetti 101, 40129 Bologna, Italy.
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Mavrocordatos, Perret. Quantitative and qualitative characterization of aquatic iron oxyhydroxide particles by EF-TEM. J Microsc 2008. [DOI: 10.1046/j.1365-2818.1998.00345.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Watanabe M, Ackland DW, Burrows A, Kiely CJ, Williams DB, Krivanek OL, Dellby N, Murfitt MF, Szilagyi Z. Improvements in the X-ray analytical capabilities of a scanning transmission electron microscope by spherical-aberration correction. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2006; 12:515-526. [PMID: 19830944 DOI: 10.1017/s1431927606060703] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A Nion spherical-aberration (Cs) corrector was recently installed on Lehigh University's 300-keV cold field-emission gun (FEG) Vacuum Generators HB 603 dedicated scanning transmission electron microscope (STEM), optimized for X-ray analysis of thin specimens. In this article, the impact of the Cs-corrector on X-ray analysis is theoretically evaluated, in terms of expected improvements in spatial resolution and analytical sensitivity, and the calculations are compared with initial experimental results. Finally, the possibilities of atomic-column X-ray analysis in a Cs-corrected STEM are discussed.
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Affiliation(s)
- M Watanabe
- Department of Materials Science and Engineering/Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, PA 18015, USA.
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Friel JJ, Lyman CE. X-ray mapping in electron-beam instruments. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2006; 12:2-25. [PMID: 17481338 DOI: 10.1017/s1431927606060211] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Accepted: 11/07/2005] [Indexed: 05/15/2023]
Abstract
This review traces the development of X-ray mapping from its beginning 50 years ago through current analysis procedures that can reveal otherwise obscure elemental distributions and associations. X-ray mapping or compositional imaging of elemental distributions is one of the major capabilities of electron beam microanalysis because it frees the operator from the necessity of making decisions about which image features contain elements of interest. Elements in unexpected locations, or in unexpected association with other elements, may be found easily without operator bias as to where to locate the electron probe for data collection. X-ray mapping in the SEM or EPMA may be applied to bulk specimens at a spatial resolution of about 1 microm. X-ray mapping of thin specimens in the TEM or STEM may be accomplished at a spatial resolution ranging from 2 to 100 nm, depending on specimen thickness and the microscope. Although mapping has traditionally been considered a qualitative technique, recent developments demonstrate the quantitative capabilities of X-ray mapping techniques. Moreover, the long-desired ability to collect and store an entire spectrum at every pixel is now a reality, and methods for mining these data are rapidly being developed.
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Affiliation(s)
- John J Friel
- Princeton Gamma Tech, C/N 863, Princeton, NJ 08542, USA
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Watanabe M, Williams DB. The quantitative analysis of thin specimens: a review of progress from the Cliff-Lorimer to the new zeta-factor methods. J Microsc 2006; 221:89-109. [PMID: 16499549 DOI: 10.1111/j.1365-2818.2006.01549.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A new quantitative thin-film X-ray analysis procedure termed the zeta-factor method is proposed. This new zeta-factor method overcomes the two major limitations of the conventional Cliff-Lorimer method for quantification: (1) use of pure-element rather than multielement, thin-specimen standards and (2) built-in X-ray absorption correction with simultaneous thickness determination. Combined with a universal, standard, thin specimen, a series of zeta-factors covering a significant fraction of the periodic table can be estimated. This zeta-factor estimation can also provide information about both the detector efficiency and the microscope-detector interface system. Light-element analysis can also be performed more easily because of the built-in absorption correction. Additionally, the new zeta-factor method has several advantages over the Cliff-Lorimer ratio method because information on the specimen thickness at the individual analysis points is produced simultaneously with compositions, thus permitting concurrent determination of the spatial resolution and the analytical sensitivity. In this work, details of the zeta-factor method and how it improves on the Cliff-Lorimer approach are demonstrated, along with several applications.
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Affiliation(s)
- M Watanabe
- Department of Materials Science and Engineering/Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, PA 18015, U.S.A.
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Spatial resolution of electron probe X-ray microanalysis on sections of organic (biological) material. Ultramicroscopy 1999. [DOI: 10.1016/s0304-3991(99)00005-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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