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Şentürk DG, De Backer A, Van Aert S. Element specific atom counting for heterogeneous nanostructures: Combining multiple ADF STEM images for simultaneous thickness and composition determination. Ultramicroscopy 2024; 259:113941. [PMID: 38387236 DOI: 10.1016/j.ultramic.2024.113941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/15/2024] [Accepted: 02/18/2024] [Indexed: 02/24/2024]
Abstract
In this paper, a methodology is presented to count the number of atoms in heterogeneous nanoparticles based on the combination of multiple annular dark field scanning transmission electron microscopy (ADF STEM) images. The different non-overlapping annular detector collection regions are selected based on the principles of optimal statistical experiment design for the atom-counting problem. To count the number of atoms, the total intensities of scattered electrons for each atomic column, the so-called scattering cross-sections, are simultaneously compared with simulated library values for the different detector regions by minimising the squared differences. The performance of the method is evaluated for simulated Ni@Pt and Au@Ag core-shell nanoparticles. Our approach turns out to be a dose efficient alternative for the investigation of beam-sensitive heterogeneous materials as compared to the combination of ADF STEM and energy dispersive X-ray spectroscopy.
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Affiliation(s)
- D G Şentürk
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - A De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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Firoozabadi S, Kükelhan P, Beyer A, Lehr J, Volz K. Quantitative composition determination by ADF-STEM at a low angular regime: a combination of EFSTEM and 4DSTEM. Ultramicroscopy 2022; 240:113550. [DOI: 10.1016/j.ultramic.2022.113550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/26/2022] [Accepted: 05/04/2022] [Indexed: 10/18/2022]
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3
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Grieb T, Krause FF, Müller-Caspary K, Ahl JP, Schowalter M, Oppermann O, Hertkorn J, Engl K, Rosenauer A. Angle-dependence of ADF-STEM intensities for chemical analysis of InGaN/GaN. Ultramicroscopy 2022; 238:113535. [DOI: 10.1016/j.ultramic.2022.113535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/08/2022] [Accepted: 04/17/2022] [Indexed: 11/30/2022]
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Zhang Y, Zhang W, Sun Y, Yu H, Lu J, Lin N, Wang Z, Pan N, Wang X, Ma C. Study of interfacial random strain fields in core-shell ZnO nanowires by scanning transmission electron microscopy. Micron 2020; 133:102862. [PMID: 32155571 DOI: 10.1016/j.micron.2020.102862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/04/2020] [Accepted: 03/04/2020] [Indexed: 10/24/2022]
Abstract
Imaging strain fields at the nanoscale is crucial for understanding the physical properties as well as the performance of oxide heterostructures and electronic devices. Based on scanning transmission electron microscopy (STEM) techniques, we successfully imaged the random strain field at the interface of core-shell ZnO nanowires. Combining experimental observations and image simulations, we find that the strain contrast originates from dechanneling of electrons and increased diffuse scattering induced by static atomic displacements. For a thin sample with a random strain field, a positive strain contrast appears in the low-angle annular dark-field (LAADF) image and a negative contrast in the high-angle annular dark-field (HAADF) image, but for a thick sample (> 120 nm), the positive contrast always occurs in both the LAADF and HAADF images. Through the analysis of the relationship between strain contrast and various parameters, we also discuss the optimum experimental condition for imaging random strain fields.
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Affiliation(s)
- Yongsen Zhang
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, China
| | - Wujun Zhang
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, China
| | - Yuzhou Sun
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, China
| | - Hongchun Yu
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, China
| | - Jiangbo Lu
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710119, China
| | - Nan Lin
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, China
| | - Zuyong Wang
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, China
| | - Nan Pan
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Anhui, 230026, China
| | - Xiaoping Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Anhui, 230026, China
| | - Chao Ma
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, China.
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Kükelhan P, Hepp T, Firoozabadi S, Beyer A, Volz K. Composition determination for quaternary III-V semiconductors by aberration-corrected STEM. Ultramicroscopy 2019; 206:112814. [PMID: 31310886 DOI: 10.1016/j.ultramic.2019.112814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/04/2019] [Accepted: 07/07/2019] [Indexed: 10/26/2022]
Abstract
Quantitative scanning transmission electron microscopy (STEM) is a powerful tool for the characterization of nano-materials. Absolute composition determination for ternary III-V semiconductors by direct comparison of experiment and simulation is well established. Here, we show a method to determine the composition of quaternary III-V semiconductors with two elements on each sub lattice from the intensities of one STEM image. As an example, this is applied to (GaIn)(AsBi). The feasibility of the method is shown in a simulation study that also explores the influence of detector angles and specimen thickness. Additionally, the method is applied to an experimental STEM image of a (GaIn)(AsBi) quantum well grown by metal organic vapour phase epitaxy. The obtained concentrations are in good agreement with X-ray diffraction and photoluminescence results.
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Affiliation(s)
- P Kükelhan
- Materials Science Centre and Faculty of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg, Germany
| | - T Hepp
- Materials Science Centre and Faculty of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg, Germany
| | - S Firoozabadi
- Materials Science Centre and Faculty of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg, Germany
| | - A Beyer
- Materials Science Centre and Faculty of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg, Germany.
| | - K Volz
- Materials Science Centre and Faculty of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg, Germany
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Simultaneous determination of local thickness and composition for ternary III-V semiconductors by aberration-corrected STEM. Ultramicroscopy 2019; 201:49-57. [PMID: 30927691 DOI: 10.1016/j.ultramic.2019.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/08/2019] [Accepted: 03/14/2019] [Indexed: 11/24/2022]
Abstract
Scanning transmission electron microscopy (STEM) is a suitable method for the quantitative characterization of nanomaterials. For an absolute composition determination on an atomic scale, the thickness of the specimen has to be known locally with high accuracy. Here, we propose a method to determine both thickness and composition of ternary III-V semiconductors locally from one STEM image as shown for the example material systems Ga(AsBi) and (GaIn)As. In a simulation study, the feasibility of the method is proven and the influence of specimen thickness and detector angles used is investigated. An application to an experimental STEM image of a Ga(AsBi) quantum well grown by metal organic vapour phase epitaxy yields an excellent agreement with composition results from high resolution X-ray diffraction.
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Composition determination of semiconductor alloys towards atomic accuracy by HAADF-STEM. Ultramicroscopy 2019; 200:84-96. [PMID: 30844539 DOI: 10.1016/j.ultramic.2019.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/21/2018] [Accepted: 02/12/2019] [Indexed: 11/23/2022]
Abstract
This paper presents a comprehensive investigation of an extended method to determine composition of materials by scanning transmission electron microscopy (STEM) high angle annular darkfield (HAADF) images and using complementary multislice simulations. The main point is to understand the theoretical capabilities of the algorithm and address the intrinsic limitations of using STEM HAADF intensities for composition determination. A special focus is the potential of the method regarding single-atom accuracy. All-important experimental parameters are included into the multislice simulations to ensure the best possible fit between simulation and experiment. To demonstrate the capabilities of the extended method, results for three different technical important semiconductor samples are presented. Overall the method shows a high lateral resolution combined with a high accuracy towards single-atom accuracy.
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Belz J, Beyer A, Volz K. Atomic-scale 3D reconstruction of antiphase boundaries in GaP on (001) silicon by STEM. Micron 2018; 114:32-41. [PMID: 30075415 DOI: 10.1016/j.micron.2018.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 11/29/2022]
Abstract
In order to overcome the limitations of silicon-based electronics, the integration of optically active III-V compounds is a promising approach. Nonetheless, their integration is far from trivial and control as well as understanding of corresponding growth kinetics, and in particular the occurrence and termination of antiphase defects, is of great relevance. In this work, we focus on the three-dimensional reconstruction of such boundaries in gallium phosphide from single scanning transmission electron microscopy images. In the high angle annular dark-field imaging mode, the appearance of these antiphase boundaries is strongly determined by the chemical composition of each atomic column and reflects the ratio of transmitted anti- to mainphase. Therefore it is possible to translate measured intensities to the depth location of these boundaries by utilizing simulation data. The necessary spatial resolution for these column-by-column mappings is achieved via electron optical aberration correction within the microscope. Hence, the complete 3D orientation of these defects can be measured at atomic resolution and correlated to growth parameters. Finally, we present a method to reconstruct large areas from well sampled images and retrieve information about complex embedded nanoscale structures at the atomic scale.
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Affiliation(s)
- Jürgen Belz
- Faculty of Physics and Materials Science Center, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg, Hessen, 35032, Germany.
| | - Andreas Beyer
- Faculty of Physics and Materials Science Center, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg, Hessen, 35032, Germany
| | - Kerstin Volz
- Faculty of Physics and Materials Science Center, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg, Hessen, 35032, Germany
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Walther T, Jones L. Preface to special issue on Microscopy of Semiconducting Materials 2017 (MSM-XX). J Microsc 2017; 268:221-224. [PMID: 29154503 DOI: 10.1111/jmi.12665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Thomas Walther
- Dept. Electronic & Electrical Engineering, University of Sheffield
| | - Lewys Jones
- Department of Materials, University of Oxford
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