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MacArthur KE, Yankovich AB, Béché A, Luysberg M, Brown HG, Findlay SD, Heggen M, Allen LJ. Optimizing Experimental Conditions for Accurate Quantitative Energy-Dispersive X-ray Analysis of Interfaces at the Atomic Scale. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-15. [PMID: 33843542 DOI: 10.1017/s1431927621000246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The invention of silicon drift detectors has resulted in an unprecedented improvement in detection efficiency for energy-dispersive X-ray (EDX) spectroscopy in the scanning transmission electron microscope. The result is numerous beautiful atomic-scale maps, which provide insights into the internal structure of a variety of materials. However, the task still remains to understand exactly where the X-ray signal comes from and how accurately it can be quantified. Unfortunately, when crystals are aligned with a low-order zone axis parallel to the incident beam direction, as is necessary for atomic-resolution imaging, the electron beam channels. When the beam becomes localized in this way, the relationship between the concentration of a particular element and its spectroscopic X-ray signal is generally nonlinear. Here, we discuss the combined effect of both spatial integration and sample tilt for ameliorating the effects of channeling and improving the accuracy of EDX quantification. Both simulations and experimental results will be presented for a perovskite-based oxide interface. We examine how the scattering and spreading of the electron beam can lead to erroneous interpretation of interface compositions, and what approaches can be made to improve our understanding of the underlying atomic structure.
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Affiliation(s)
- Katherine E MacArthur
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Andrew B Yankovich
- Department of Physics, Chalmers University of Technology, SE-412 96Gothenburg, Sweden
| | - Armand Béché
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020Antwerp, Belgium
| | - Martina Luysberg
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Hamish G Brown
- National Centre for Electron Microscopy, the Molecular Foundry, Lawrence Berkeley National Lab, Berkeley, CA94720, USA
| | - Scott D Findlay
- School of Physics and Astronomy, Monash University, Clayton, VIC3800, Australia
| | - Marc Heggen
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Leslie J Allen
- School of Physics, University of Melbourne, Parkville, VIC3010, Australia
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Paulauskas T, Pačebutas V, Butkutė R, Čechavičius B, Naujokaitis A, Kamarauskas M, Skapas M, Devenson J, Čaplovičová M, Vretenár V, Li X, Kociak M, Krotkus A. Atomic-Resolution EDX, HAADF, and EELS Study of GaAs 1-xBi x Alloys. NANOSCALE RESEARCH LETTERS 2020; 15:121. [PMID: 32451638 PMCID: PMC7248167 DOI: 10.1186/s11671-020-03349-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/10/2020] [Indexed: 06/11/2023]
Abstract
The distribution of alloyed atoms in semiconductors often deviates from a random distribution which can have significant effects on the properties of the materials. In this study, scanning transmission electron microscopy techniques are employed to analyze the distribution of Bi in several distinctly MBE grown GaAs1-xBix alloys. Statistical quantification of atomic-resolution HAADF images, as well as numerical simulations, are employed to interpret the contrast from Bi-containing columns at atomically abrupt (001) GaAs-GaAsBi interface and the onset of CuPt-type ordering. Using monochromated EELS mapping, bulk plasmon energy red-shifts are examined in a sample exhibiting phase-separated domains. This suggests a simple method to investigate local GaAsBi unit-cell volume expansions and to complement standard X-ray-based lattice-strain measurements. Also, a single-variant CuPt-ordered GaAsBi sample grown on an offcut substrate is characterized with atomic scale compositional EDX mappings, and the order parameter is estimated. Finally, a GaAsBi alloy with a vertical Bi composition modulation is synthesized using a low substrate rotation rate. Atomically, resolved EDX and HAADF imaging shows that the usual CuPt-type ordering is further modulated along the [001] growth axis with a period of three lattice constants. These distinct GaAsBi samples exemplify the variety of Bi distributions that can be achieved in this alloy, shedding light on the incorporation mechanisms of Bi atoms and ways to further develop Bi-containing III-V semiconductors.
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Affiliation(s)
- Tadas Paulauskas
- Center for Physical Sciences and Technology, Saulėtekio al. 3, Vilnius, Lithuania.
| | - Vaidas Pačebutas
- Center for Physical Sciences and Technology, Saulėtekio al. 3, Vilnius, Lithuania
| | - Renata Butkutė
- Center for Physical Sciences and Technology, Saulėtekio al. 3, Vilnius, Lithuania
| | | | - Arnas Naujokaitis
- Center for Physical Sciences and Technology, Saulėtekio al. 3, Vilnius, Lithuania
| | | | - Martynas Skapas
- Center for Physical Sciences and Technology, Saulėtekio al. 3, Vilnius, Lithuania
| | - Jan Devenson
- Center for Physical Sciences and Technology, Saulėtekio al. 3, Vilnius, Lithuania
| | - Mária Čaplovičová
- STU Centre for Nanodiagnostics, University Science Park Bratislava Centre, Slovak University of Technology, Vazovova 5, Bratislava, Slovakia
| | - Viliam Vretenár
- STU Centre for Nanodiagnostics, University Science Park Bratislava Centre, Slovak University of Technology, Vazovova 5, Bratislava, Slovakia
| | - Xiaoyan Li
- Solid State Physics Laboratory, University of Paris SUD, 91400, Orsay, France
| | - Mathieu Kociak
- Solid State Physics Laboratory, University of Paris SUD, 91400, Orsay, France
| | - Arūnas Krotkus
- Center for Physical Sciences and Technology, Saulėtekio al. 3, Vilnius, Lithuania
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Varambhia A, Jones L, London A, Ozkaya D, Nellist PD, Lozano-Perez S. Determining EDS and EELS partial cross-sections from multiple calibration standards to accurately quantify bi-metallic nanoparticles using STEM. Micron 2018; 113:69-82. [DOI: 10.1016/j.micron.2018.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/22/2018] [Accepted: 06/22/2018] [Indexed: 11/15/2022]
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4
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MacArthur KE, Brown HG, Findlay SD, Allen LJ. Probing the effect of electron channelling on atomic resolution energy dispersive X-ray quantification. Ultramicroscopy 2017; 182:264-275. [DOI: 10.1016/j.ultramic.2017.07.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/28/2017] [Accepted: 07/30/2017] [Indexed: 11/29/2022]
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Slater TJ, Janssen A, Camargo PH, Burke MG, Zaluzec NJ, Haigh SJ. STEM-EDX tomography of bimetallic nanoparticles: A methodological investigation. Ultramicroscopy 2016; 162:61-73. [DOI: 10.1016/j.ultramic.2015.10.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/01/2015] [Accepted: 10/11/2015] [Indexed: 11/16/2022]
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6
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MacArthur KE, Slater TJA, Haigh SJ, Ozkaya D, Nellist PD, Lozano-Perez S. Quantitative Energy-Dispersive X-Ray Analysis of Catalyst Nanoparticles Using a Partial Cross Section Approach. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:71-81. [PMID: 26754480 DOI: 10.1017/s1431927615015494] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The new generation of energy-dispersive X-ray (EDX) detectors with higher count rates than ever before, paves the way for a new approach to quantitative elemental analysis in the scanning transmission electron microscope. Here we demonstrate a method of calculating partial cross sections for use in quantifying EDX data, beneficial especially because of the simplicity of its implementation. Applying this approach to acid-leached PtCo catalyst nanoparticles leads to quantitative determination of the Pt surface enrichment.
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Affiliation(s)
| | - Thomas J A Slater
- 2Materials Science Centre,University of Manchester,Manchester M13 9PL,UK
| | - Sarah J Haigh
- 2Materials Science Centre,University of Manchester,Manchester M13 9PL,UK
| | - Dogan Ozkaya
- 3Johnson Matthey Technology Centre,Blounts Court Road,Sonning Common,Reading RG4 9NH,Reading,UK
| | - Peter D Nellist
- 1Department of Materials,University of Oxford,Parks Road,Oxford OX1 3PH,UK
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Energy dispersive X-ray analysis on an absolute scale in scanning transmission electron microscopy. Ultramicroscopy 2015; 157:21-6. [DOI: 10.1016/j.ultramic.2015.05.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 05/06/2015] [Accepted: 05/12/2015] [Indexed: 11/23/2022]
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Kim C, Phillips PJ, Key B, Yi T, Nordlund D, Yu YS, Bayliss RD, Han SD, He M, Zhang Z, Burrell AK, Klie RF, Cabana J. Direct Observation of Reversible Magnesium Ion Intercalation into a Spinel Oxide Host. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:3377-3384. [PMID: 25882455 DOI: 10.1002/adma.201500083] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/07/2015] [Indexed: 06/04/2023]
Affiliation(s)
- Chunjoong Kim
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Patrick J Phillips
- Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Baris Key
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Tanghong Yi
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Dennis Nordlund
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Young-Sang Yu
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, 60607, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ryan D Bayliss
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Sang-Don Han
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Meinan He
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, 60439, USA
- Mechanical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Zhengcheng Zhang
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Anthony K Burrell
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Robert F Klie
- Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Jordi Cabana
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, 60607, USA
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