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Banerjee P, Roy C, Jiménez JJ, Morales FM, Bhattacharyya S. Atomically resolved 3D structural reconstruction of small quantum dots. NANOSCALE 2021; 13:7550-7557. [PMID: 33928976 DOI: 10.1039/d1nr00466b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Semiconducting quantum dots (QDs) have potential applications in light-emitting diodes, single-photon sources and quantum computing due to shape-dependent (opto) electronic properties. Atomic resolution 3D-structure determination is important in understanding growth kinetics and improving device performance. 3D-reconstruction of large QDs was reported using characterization techniques like atomic force microscopy, atom probe tomography and tilt series electron tomography, but, still, atomic resolution tomography of QDs, especially those sized below 10 nm, is a challenge. Inline-3D-holography is an emerging and promising technique to perform atomic resolution tomography at low electron doses. In the present study, atomically resolved 3D structures of QDs were reconstructed using inline-3D-holography, implemented on InN QDs (<10 nm) grown on a Si substrate. The residual amorphous glue distorts the exit surface geometry; hence an error correction method was proposed. This is the first experimental evidence of pre-pyramid shaped 3D structure of QDs sized below 10 nm that supports theoretical predictions.
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Affiliation(s)
- Pritam Banerjee
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
| | - Chiranjit Roy
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
| | - Juan Jesús Jiménez
- IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cádiz, Spain and Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, 11510 Cádiz, Spain
| | - Francisco Miguel Morales
- IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cádiz, Spain and Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, 11510 Cádiz, Spain
| | - Somnath Bhattacharyya
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
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Atomically resolved tomographic reconstruction of nanoparticles from single projection: Influence of amorphous carbon support. Ultramicroscopy 2020; 221:113177. [PMID: 33290981 DOI: 10.1016/j.ultramic.2020.113177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/15/2020] [Accepted: 11/21/2020] [Indexed: 11/22/2022]
Abstract
Nanoparticles have a wide range of applications due to their unique geometry and arrangement of atoms. For a precise structure-property correlation, information regarding atomically resolved 3D structures of nanoparticles is utmost beneficial. Though modern aberration-corrected transmission electron microscopes can resolve atoms with the sub-angstrom resolution, an atomic-scale 3D reconstruction of a nanoparticle using Scanning Transmission Electron Microscopy (STEM) based tomographic method faces hurdles due to high electron irradiation damage and "missing-wedge". Instead, inline 3D holography based tomographic reconstructions from single projection registered at low electron doses is more suitable for defining atomic positions at nanostructures. Nanoparticles are generally supported on amorphous carbon film for Transmission Electron Microscopy (TEM) experiments. However, neglecting the influence of carbon film on the tomographic reconstruction of the nanoparticle may lead to ambiguity. To address this issue, the effect of amorphous carbon support was quantitatively studied using simulations and experiments and it was revealed that increasing thickness and/or density of carbon support increases distortion in tomograms.
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Li S, Chang Y, Wang Y, Xu Q, Ge B. A review of sample thickness effects on high-resolution transmission electron microscopy imaging. Micron 2020; 130:102813. [DOI: 10.1016/j.micron.2019.102813] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/18/2019] [Accepted: 12/18/2019] [Indexed: 11/15/2022]
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Shen RH, Ming WQ, Chen JH, He YT, Mi SB, Ma CS. Feasible atomic-resolution electron tomography for general crystal surfaces by quantitative reconstruction from a high-resolution image. Ultramicroscopy 2019; 205:27-38. [PMID: 31234100 DOI: 10.1016/j.ultramic.2019.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 06/03/2019] [Accepted: 06/09/2019] [Indexed: 11/19/2022]
Abstract
Whether or not the 3-dimensional surface morphologies of a crystal sample can be reconstructed at atomic-scale from a single 2-dimensional image becomes an interesting issue in high-resolution transmission electron microscopy, after the work by Jia et al. [1]. Here we propose an improved and self-validated algorithm to enhance such an electron tomography method and to make it applicable to more general crystal surfaces even with thin amorphous layers. Our study shows that a resolution in the beam (z) direction and a confidence level have to be defined and estimated after performing tomographic reconstruction in order to evaluate the quality and the reliability of its result. Applying the proposed procedure to the Si[110] image to recover the surface morphologies of a silicon crystal with amorphous contamination, the obtained results show that an atomic-resolution of 0.384 nm in the z-direction and a high confidence level of 95% are achieved for imaging the Si-surface structures, quantitatively described by tomographic parameters, i.e., the height (defocus) and the thickness (atom number) of Si-atomic columns.
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Affiliation(s)
- R H Shen
- Centre for High Resolution Electron Microscopy, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - W Q Ming
- Centre for High Resolution Electron Microscopy, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - J H Chen
- Centre for High Resolution Electron Microscopy, College of Materials Science and Engineering, Hunan University, Changsha 410082, China.
| | - Y T He
- Centre for High Resolution Electron Microscopy, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - S B Mi
- State Key Laboratory for Mechanical Behavior of Materials & School of Microelectronics, Xi'an Jiaotong University, Xi'an 710054, China
| | - C S Ma
- State Key Laboratory for Mechanical Behavior of Materials & School of Microelectronics, Xi'an Jiaotong University, Xi'an 710054, China
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Zhang Q, Jin C, Xu H, Zhang L, Ren X, Ouyang Y, Wang X, Yue X, Lin F. Multiple-ellipse fitting method to precisely measure the positions of atomic columns in a transmission electron microscope image. Micron 2018; 113:99-104. [DOI: 10.1016/j.micron.2018.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 06/25/2018] [Accepted: 06/25/2018] [Indexed: 10/28/2022]
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Wen C, Ma YJ. Determination of atomic-scale chemical composition at semiconductor heteroepitaxial interfaces by high-resolution transmission electron microscopy. Micron 2018; 106:48-58. [PMID: 29331739 DOI: 10.1016/j.micron.2018.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/02/2018] [Accepted: 01/06/2018] [Indexed: 11/15/2022]
Abstract
The determination of atomic structures and further quantitative information such as chemical compositions at atomic scale for semiconductor defects or heteroepitaxial interfaces can provide direct evidence to understand their formation, modification, and/or effects on the properties of semiconductor films. The commonly used method, high-resolution transmission electron microscopy (HRTEM), suffers from difficulty in acquiring images that correctly show the crystal structure at atomic resolution, because of the limitation in microscope resolution or deviation from the Scherzer-defocus conditions. In this study, an image processing method, image deconvolution, was used to achieve atomic-resolution (∼1.0 Å) structure images of small lattice-mismatch (∼1.0%) AlN/6H-SiC (0001) and large lattice-mismatch (∼8.5%) AlSb/GaAs (001) heteroepitaxial interfaces using simulated HRTEM images of a conventional 300-kV field-emission-gun transmission electron microscope under non-Scherzer-defocus conditions. Then, atomic-scale chemical compositions at the interface were determined for the atomic intermixing and Lomer dislocation with an atomic step by analyzing the deconvoluted image contrast. Furthermore, the effect of dynamical scattering on contrast analysis was also evaluated for differently weighted atomic columns in the compositions.
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Affiliation(s)
- C Wen
- School of Science, Southwest University of Science and Technology, Mianyang, 621010, China.
| | - Y J Ma
- Analytical and Testing Center, Southwest University of Science and Technology, Mianyang, 621010, China
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Jia CL, Mi SB, Barthel J, Wang DW, Dunin-Borkowski RE, Urban KW, Thust A. Determination of the 3D shape of a nanoscale crystal with atomic resolution from a single image. NATURE MATERIALS 2014; 13:1044-9. [PMID: 25242534 DOI: 10.1038/nmat4087] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 08/12/2014] [Indexed: 05/16/2023]
Abstract
Although the overall atomic structure of a nanoscale crystal is in principle accessible by modern transmission electron microscopy, the precise determination of its surface structure is an intricate problem. Here, we show that aberration-corrected transmission electron microscopy, combined with dedicated numerical evaluation procedures, allows the three-dimensional shape of a thin MgO crystal to be determined from only one single high-resolution image. The sensitivity of the reconstruction procedure is not only sufficient to reveal the surface morphology of the crystal with atomic resolution, but also to detect the presence of adsorbed impurity atoms. The single-image approach that we introduce offers important advantages for three-dimensional studies of radiation-sensitive crystals.
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Affiliation(s)
- C L Jia
- 1] International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, China [2] Peter Grünberg Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany [3] Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - S B Mi
- International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, China
| | - J Barthel
- 1] Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany [2] Central Facility for Electron Microscopy, RWTH Aachen University, Ahornstr. 55 52074 Aachen, Germany
| | - D W Wang
- International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, China
| | - R E Dunin-Borkowski
- 1] Peter Grünberg Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany [2] Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - K W Urban
- 1] Peter Grünberg Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany [2] Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - A Thust
- 1] Peter Grünberg Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany [2] Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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