1
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Grieb T, Krause FF, Mehrtens T, Mahr C, Gerken B, Schowalter M, Freitag B, Rosenauer A. GaN atomic electric fields from a segmented STEM detector: Experiment and simulation. J Microsc 2024; 295:140-146. [PMID: 38372408 DOI: 10.1111/jmi.13276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 01/31/2024] [Indexed: 02/20/2024]
Abstract
Atomic electric fields in a thin GaN sample are measured with the centre-of-mass approach in 4D-scanning transmission electron microscopy (4D-STEM) using a 12-segmented STEM detector in a Spectra 300 microscope. The electric fields, charge density and potential are compared to simulations and an experimental measurement using a pixelated 4D-STEM detector. The segmented detector benefits from a high recording speed, which enables measurements at low radiation doses. However, there is measurement uncertainty due to the limited number of segments analysed in this study.
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Affiliation(s)
- Tim Grieb
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Florian F Krause
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Thorsten Mehrtens
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Christoph Mahr
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Beeke Gerken
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Marco Schowalter
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Bert Freitag
- Thermo Fisher Scientific, Eindhoven, The Netherlands
| | - Andreas Rosenauer
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
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2
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Cooper D, Bruas L, Bryan M, Boureau V. Measuring electrical properties in semiconductor devices by pixelated STEM and off-axis electron holography (or convergent beams vs. plane waves). Micron 2024; 179:103594. [PMID: 38340549 DOI: 10.1016/j.micron.2024.103594] [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: 12/04/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024]
Abstract
We demonstrate the use of both pixelated differential phase contrast (DPC) scanning transmission electron microscopy (STEM) and off-axis electron holography (EH) for the measurement of electric fields and assess the advantages and limitations of each technique when applied to technologically relevant samples. Three different types of samples are examined, firstly a simple highly-doped Si pn junction. Then a SiGe superlattice is examined to evaluate the effects of the mean inner potential on the measured signal. Finally, an InGaN/GaN microwire light-emitting diode (LED) device is examined which has a polarization field, variations of mean inner potential and a wurtzite crystal lattice. We discuss aspects such as spatial resolution and sensitivity, and the concept of pseudo-field is defined. However, the most important point is the need to limit the influence of diffraction contrast to obtain accurate measurements. In this respect, the use of a plane electron wave for EH is clearly beneficial when compared to the use of a convergent beam for pixelated DPC STEM.
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Affiliation(s)
- David Cooper
- Universite Grenoble Alpes, CEA, LETI, F-38000 Grenoble, France.
| | - Lucas Bruas
- Universite Grenoble Alpes, CEA, LETI, F-38000 Grenoble, France
| | - Matthew Bryan
- Universite Grenoble Alpes, CEA, LETI, F-38000 Grenoble, France
| | - Victor Boureau
- Universite Grenoble Alpes, CEA, LETI, F-38000 Grenoble, France; Interdisciplinary Center for Electron Microscopy, EPFL, 1015 Lausanne, Switzerland
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3
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Susana L, Gloter A, Tencé M, Zobelli A. Direct Quantifying Charge Transfer by 4D-STEM: A Study on Perfect and Defective Hexagonal Boron Nitride. ACS NANO 2024; 18:7424-7432. [PMID: 38408195 DOI: 10.1021/acsnano.3c10299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Four-dimensional scanning transmission electron microscopy (4D-STEM) offers an attractive approach to simultaneously obtain precise structural determinations and capture details of local electric fields and charge densities. However, accurately extracting quantitative data at the atomic scale poses challenges, primarily due to probe propagation and size-related effects, which may even lead to misinterpretations of qualitative effects. In this study, we present a comprehensive analysis of electric fields and charge densities in both pristine and defective h-BN flakes. Through a combination of experiments and first-principle simulations, we demonstrate that while precise charge quantification at individual atomic sites is hindered by probe effects, 4D-STEM can directly measure charge transfer phenomena at the monolayer edge with sensitivity down to a few tenths of an electron and a spatial resolution on the order of a few angstroms.
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Affiliation(s)
- Laura Susana
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Alexandre Gloter
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Marcel Tencé
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Alberto Zobelli
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette, France
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4
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Li C, Mu X, Korytov M, Alexandrou I, Bosch EGT. Differential phase contrast (DPC) mapping electric fields: Optimising experimental conditions. J Microsc 2024; 293:177-188. [PMID: 38353282 DOI: 10.1111/jmi.13271] [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: 06/26/2023] [Revised: 01/04/2024] [Accepted: 01/19/2024] [Indexed: 02/20/2024]
Abstract
DPC in Scanning Transmission Electron Microscopy (STEM) is a valuable method for mapping the electric fields in semiconductor materials. However, optimising the experimental conditions can be challenging. In this paper, we test and compare critical experimental parameters, including the convergence angle, camera length, acceleration voltage, sample configuration, and orientation using a four-quadrant segmented detector and a Si specimen containing layers of different As concentrations. The DPC measurements show a roughly linear correlation with the estimated electric fields, until the field gets close to the detection limitation, which is ∼0.5 mV/nm with a sample thickness of ∼145 nm. These results can help inform which technique to use for different user cases: When the electric field at a planar junction is above ∼0.5 mV/nm, DPC with a segmented detector is practical for electric field mapping. With a planar junction, the DPC signal-to-noise ratio can be increased by increasing the specimen thickness. However, for semiconductor devices with electric fields smaller than ∼0.5 mV/nm, or for devices containing curved junctions, DPC is unreliable and techniques with higher sensitivity will need to be explored, such as 4D STEM using a pixelated detector.
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Affiliation(s)
- Chen Li
- Thermo Fisher Scientific, Eindhoven, the Netherlands
| | - Xiaoke Mu
- Thermo Fisher Scientific, Eindhoven, the Netherlands
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5
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Ii S. Quantitative Characterization by Transmission Electron Microscopy and Its Application to Interfacial Phenomena in Crystalline Materials. MATERIALS (BASEL, SWITZERLAND) 2024; 17:578. [PMID: 38591374 PMCID: PMC10856096 DOI: 10.3390/ma17030578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/13/2024] [Accepted: 01/18/2024] [Indexed: 04/10/2024]
Abstract
This paper reviews quantitative characterization via transmission electron microscopy (TEM) and its application to interfacial phenomena based on the results obtained through the studies. Several signals generated by the interaction between the specimen and the electron beam with a probe size of less than 1 nm are utilized for a quantitative analysis, which yields considerable chemical and physical information. This review describes several phenomena near the interfaces, e.g., clear solid-vapor interface (surface) segregation of yttria in the zirconia nanoparticles by an energy-dispersive X-ray spectroscopy analysis, the evaluation of the local magnetic moment at the grain boundary in terms of electron energy loss spectroscopy equipped with TEM, and grain boundary character dependence of the magnetism. The direct measurement of the stress to the dislocation transferred across the grain boundary and the microstructure evolution focused on the grain boundary formation caused by plastic deformation are discussed as examples of material dynamics associated with the grain boundary. Finally, the outlook for future investigations of interface studies, including the recent progress, is also discussed.
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Affiliation(s)
- Seiichiro Ii
- Research Center for Structural Materials, National Institute for Materials Science (NIMS), Tsukuba 305-0047, Japan
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6
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Maguire JR, McCluskey CJ, Holsgrove KM, Suna A, Kumar A, McQuaid RGP, Gregg JM. Ferroelectric Domain Wall p-n Junctions. NANO LETTERS 2023; 23:10360-10366. [PMID: 37947380 PMCID: PMC10683062 DOI: 10.1021/acs.nanolett.3c02966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/23/2023] [Accepted: 10/25/2023] [Indexed: 11/12/2023]
Abstract
We have used high-voltage Kelvin probe force microscopy to map the spatial distribution of electrical potential, dropped along curved current-carrying conducting domain walls, in x-cut single-crystal ferroelectric lithium niobate thin films. We find that in-operando potential profiles and extracted electric fields, associated with p-n junctions contained within the walls, can be fully rationalized through expected variations in wall resistivity alone. There is no need to invoke additional physics (carrier depletion zones and space-charge fields) normally associated with extrinsically doped semiconductor p-n junctions. Indeed, we argue that this should not even be expected, as inherent Fermi level differences between p and n regions, at the core of conventional p-n junction behavior, cannot occur in domain walls that are surrounded by a common matrix. This is important for domain-wall nanoelectronics, as such in-wall junctions will neither act as diodes nor facilitate transistors in the same way as extrinsic semiconducting systems do.
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Affiliation(s)
- Jesi R. Maguire
- School
of Mathematics and Physics, Queen’s
University Belfast, Belfast BT7 1NN, U.K.
| | - Conor J. McCluskey
- School
of Mathematics and Physics, Queen’s
University Belfast, Belfast BT7 1NN, U.K.
| | - Kristina M. Holsgrove
- School
of Mathematics and Physics, Queen’s
University Belfast, Belfast BT7 1NN, U.K.
| | - Ahmet Suna
- School
of Mathematics and Physics, Queen’s
University Belfast, Belfast BT7 1NN, U.K.
| | - Amit Kumar
- School
of Mathematics and Physics, Queen’s
University Belfast, Belfast BT7 1NN, U.K.
| | - Raymond G. P. McQuaid
- School
of Mathematics and Physics, Queen’s
University Belfast, Belfast BT7 1NN, U.K.
| | - J. Marty Gregg
- School
of Mathematics and Physics, Queen’s
University Belfast, Belfast BT7 1NN, U.K.
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7
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Heimes D, Chejarla VS, Ahmed S, Hüppe F, Beyer A, Volz K. Impact of beam size and diffraction effects in the measurement of long-range electric fields in crystalline samples via 4DSTEM. Ultramicroscopy 2023; 253:113821. [PMID: 37562100 DOI: 10.1016/j.ultramic.2023.113821] [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: 04/04/2023] [Revised: 06/27/2023] [Accepted: 07/25/2023] [Indexed: 08/12/2023]
Abstract
Measuring long-range electric fields by 4-dimensional scanning transmission electron microscopy (4DSTEM) is on the verge to becoming an established method, though quantifying and understanding all underlying processes remains a challenge. To gain further insight into these processes, experimental studies employing the center-of-mass (COM) method of the model system of a GaAs p-n junction are carried out in which three ranges of the semi-convergence angle α are identified, with an intermediate one where measuring the built-in potential Vbi is not feasible. STEM multislice simulations including both atomic and nm-scale fields prove that this intermediate range begins once diffraction disks start overlapping with the undiffracted beam. The range ends when the diffraction disks' intensities become so low that they do not affect the measurement significantly anymore and when high-intensity diffractions overlap the center disk completely. From simulations without influence of atoms it is concluded that measuring Vbi has advantages over measuring the electric-field strength, as the potential difference does neither show a significant dependence on the beam size, nor on the specimen thickness.
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Affiliation(s)
- Damien Heimes
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Germany
| | - Varun Shankar Chejarla
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Germany
| | - Shamail Ahmed
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Germany
| | - Franziska Hüppe
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Germany
| | - Andreas Beyer
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Germany
| | - Kerstin Volz
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Germany.
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8
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Chejarla VS, Ahmed S, Belz J, Scheunert J, Beyer A, Volz K. Measuring Spatially-Resolved Potential Drops at Semiconductor Hetero-Interfaces Using 4D-STEM. SMALL METHODS 2023; 7:e2300453. [PMID: 37246264 DOI: 10.1002/smtd.202300453] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Indexed: 05/30/2023]
Abstract
Characterizing long-range electric fields and built-in potentials in functional materials at nano to micrometer scales is of supreme importance for optimizing devices, e.g., the functionality of semiconductor hetero-structures or battery materials is determined by the electric fields established at interfaces which can also vary spatially. In this study, momentum-resolved four-dimensional scanning transmission electron microscopy (4D-STEM) is proposed for the quantification of these potentials and the optimization steps required to reach quantitative agreement with simulations for the GaAs/AlAs hetero-junction model system are shown. Using STEM the differences in the mean inner potentials (∆MIP) of two materials forming an interface and resulting dynamic diffraction effects have to be considered. This study shows that the measurement quality is significantly improved by precession, energy filtering and a off-zone-axis alignment of the specimen. Complementary simulations yielding a ∆MIP of 1.3 V confirm that the potential drop due to charge transfer at the intrinsic interface is ≈0.1 V, in agreement with experimental and theoretical values found in literture. These results show the feasibility of accurately measuring built-in potentials across hetero-interfaces of real device structures and its promising application for more complex interfaces of other polycrystalline materials on the nanometer scale.
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Affiliation(s)
- Varun Shankar Chejarla
- Department of Physics and Materials Science Center, Philipps-University Marburg, Hans-Meerwein Str. 6, 35032, Marburg, Germany
| | - Shamail Ahmed
- Department of Physics and Materials Science Center, Philipps-University Marburg, Hans-Meerwein Str. 6, 35032, Marburg, Germany
| | - Jürgen Belz
- Department of Physics and Materials Science Center, Philipps-University Marburg, Hans-Meerwein Str. 6, 35032, Marburg, Germany
| | - Jonas Scheunert
- Department of Physics and Materials Science Center, Philipps-University Marburg, Hans-Meerwein Str. 6, 35032, Marburg, Germany
| | - Andreas Beyer
- Department of Physics and Materials Science Center, Philipps-University Marburg, Hans-Meerwein Str. 6, 35032, Marburg, Germany
| | - Kerstin Volz
- Department of Physics and Materials Science Center, Philipps-University Marburg, Hans-Meerwein Str. 6, 35032, Marburg, Germany
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9
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Nordahl G, Dagenborg S, Nord M. Magnetic Field Mapping in STEM-DPC by Utilizing Artificial Neural Networks. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:303-304. [PMID: 37613524 DOI: 10.1093/micmic/ozad067.140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Gregory Nordahl
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Sivert Dagenborg
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Magnus Nord
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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10
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Chejarla VS, Ahmed S, Beyer A, Volz K. Quantification of Potential Drops Across Semiconductor Heterointerfaces Using 4D-STEM. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:330-331. [PMID: 37613207 DOI: 10.1093/micmic/ozad067.154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Varun Shankar Chejarla
- Philipps-University Marburg, Department of Physics and Materials Science Center, Marburg, Germany
| | - Shamail Ahmed
- Philipps-University Marburg, Department of Physics and Materials Science Center, Marburg, Germany
| | - Andreas Beyer
- Philipps-University Marburg, Department of Physics and Materials Science Center, Marburg, Germany
| | - Kerstin Volz
- Philipps-University Marburg, Department of Physics and Materials Science Center, Marburg, Germany
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11
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Chen L, Liang Z, Shao S, Huang Q, Tang K, Huang R. First direct observation of the built-in electric field and oxygen vacancy migration in ferroelectric Hf 0.5Zr 0.5O 2 film during electrical cycling. NANOSCALE 2023; 15:7014-7022. [PMID: 36970751 DOI: 10.1039/d2nr06582g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The wake-up and fatigue effects exhibited by ferroelectric hafnium oxide (HfO2) during electrical cycling are two of the most significant obstacles limiting its development and application. Despite a mainstream theory relating these phenomena to the migration of oxygen vacancies and the evolution of the built-in field, no supportive experimental observations from a nanoscale perspective have been reported so far. By combining differential phase contrast scanning transmission electron microscopy (DPC-STEM) and energy dispersive spectroscopy (EDS) analysis, we directly observe the migration of oxygen vacancies and the evolution of the built-in field in ferroelectric HfO2 for the first time. These solid results indicate that the wake-up effect is caused by the homogenization of oxygen vacancy distribution and weakening of the vertical built-in field whereas the fatigue effect is related to charge injection and transverse local electric field enhancement. In addition, using a low-amplitude electrical cycling scheme, we exclude field-induced phase transition from the root cause of the wake-up and fatigue in Hf0.5Zr0.5O2. With direct experimental evidence, this work clarifies the core mechanism of the wake-up and fatigue effects, which is important for the optimization of ferroelectric memory devices.
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Affiliation(s)
- Liang Chen
- School of Integrated Circuits, Peking University, Beijing 100871, China.
| | - Zhongxin Liang
- School of Integrated Circuits, Peking University, Beijing 100871, China.
| | - Shixuan Shao
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China
| | - Qianqian Huang
- School of Integrated Circuits, Peking University, Beijing 100871, China.
- Beijing Advanced Innovation Center for Integrated Circuits, Beijing 100871, China
| | - Kechao Tang
- School of Integrated Circuits, Peking University, Beijing 100871, China.
- Beijing Advanced Innovation Center for Integrated Circuits, Beijing 100871, China
| | - Ru Huang
- School of Integrated Circuits, Peking University, Beijing 100871, China.
- Beijing Advanced Innovation Center for Integrated Circuits, Beijing 100871, China
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12
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Optimized detector configurations for the reconstruction of phase-contrast images in scanning transmission electron microscopy. Ultramicroscopy 2023; 246:113670. [PMID: 36657215 DOI: 10.1016/j.ultramic.2022.113670] [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: 03/11/2022] [Revised: 12/17/2022] [Accepted: 12/26/2022] [Indexed: 01/13/2023]
Abstract
Using the differential phase contrast mechanism and anti-symmetric detector geometries it is possible to image distributions of electric and magnetic fields in a scanning transmission electron microscope. Different detector geometries can be used for imaging and, due to their efficiency, mainly ring quadrant detectors and pixelated detectors have been used in recent high resolution differential phase contrast experiments. In 4D-Scanning Transmission Electron Microscopy one uses a pixelated (2D) detector to obtain the complete scattering distribution for every (2D) image point. The accuracy of pixelated detectors increases with an increasing number of pixels, which in turn also leads to a larger amount of data that needs to be evaluated. To reduce the required numerical effort, we are looking for alternative detector geometries by further segmenting ring quadrant detectors. To compare the different geometries, their signal-to-noise ratios are calculated for an ideal STEM and several weak phase objects. Images can be obtained by combining the data of different detector pixels using a scheme similar to a reconstruction from a focal series. The procedure can be interpreted as the simplest example of ptychography including only the first-order diffraction disks. Our results show that a 50-segment annular bright-field detector can reach a signal-to-noise ratio close to that of a 128 × 128 pixelated detector, while having a significantly lower number of segments that need to be evaluated.
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13
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Wang S, Li Y, Song J, Zhang J, Ma Y. Recent progress in the electrochemical quantification of nitrophenols. J Electroanal Chem (Lausanne) 2023. [DOI: 10.1016/j.jelechem.2023.117375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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14
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da Silva BC, Sadre Momtaz Z, Monroy E, Okuno H, Rouviere JL, Cooper D, Den Hertog MI. Assessment of Active Dopants and p-n Junction Abruptness Using In Situ Biased 4D-STEM. NANO LETTERS 2022; 22:9544-9550. [PMID: 36442685 DOI: 10.1021/acs.nanolett.2c03684] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
A key issue in the development of high-performance semiconductor devices is the ability to properly measure active dopants at the nanometer scale. In a p-n junction, the abruptness of the dopant profile around the metallurgical junction directly influences the electric field. Here, a contacted nominally symmetric and highly doped (NA = ND = 9 × 1018 cm-3) silicon p-n specimen is studied through in situ biased four-dimensional scanning transmission electron microscopy (4D-STEM). Measurements of electric field, built-in voltage, depletion region width, and charge density are combined with analytical equations and finite-element simulations in order to evaluate the quality of the junction interface. It is shown that all the junction parameters measured are compatible with a linearly graded junction. This hypothesis is also consistent with the evolution of the electric field with bias as well as off-axis electron holography data. These results demonstrate that in situ biased 4D-STEM can allow a better understanding of the electrostatics of semiconductor p-n junctions with nm-scale resolution.
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Affiliation(s)
| | | | - Eva Monroy
- Université Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, F-38000Grenoble, France
| | - Hanako Okuno
- Université Grenoble Alpes, CEA, IRIG, MEM, LEMMA, F-38000Grenoble, France
| | - Jean-Luc Rouviere
- Université Grenoble Alpes, CEA, IRIG, MEM, LEMMA, F-38000Grenoble, France
| | - David Cooper
- Université Grenoble Alpes, CEA-LETI, F-38000Grenoble, France
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15
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Liu B, Hu N, Li C, Ma J, Zhang J, Yang Y, Sun D, Yin B, Cui G. Direct Observation of Li‐Ion Transport Heterogeneity Induced by Nanoscale Phase Separation in Li‐rich Cathodes of Solid‐State Batteries. Angew Chem Int Ed Engl 2022; 61:e202209626. [DOI: 10.1002/anie.202209626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Bowen Liu
- Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials Institute for New Energy Materials and Low Carbon Technologies School of Materials Science and Engineering Tianjin University of Technology Tianjin 300384 China
| | - Naifang Hu
- Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China
| | - Chao Li
- Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials Institute for New Energy Materials and Low Carbon Technologies School of Materials Science and Engineering Tianjin University of Technology Tianjin 300384 China
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Renewable Energy Conversion and Storage Center College of Chemistry Nankai University Tianjin 300071 China
| | - Jun Ma
- Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China
- Shandong Energy Institute Qingdao 266101 China
| | - Jianwei Zhang
- Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials Institute for New Energy Materials and Low Carbon Technologies School of Materials Science and Engineering Tianjin University of Technology Tianjin 300384 China
| | - Yuan Yang
- Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China
| | - Deye Sun
- Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China
| | - Bangxun Yin
- Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China
| | - Guanglei Cui
- Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China
- Shandong Energy Institute Qingdao 266101 China
- Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China
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16
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Liu B, Hu N, Li C, Ma J, Zhang J, Yang Y, Sun D, Yin B, Cui G. Direct Observation of Li‐Ion Transport Heterogeneity Induced by Nanoscale Phase Separation in Li‐rich Cathodes of Solid‐State Batteries. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Bowen Liu
- Tianjin University of Technology Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials and Low Carbon Technologies, School of Materials Science and Engineering CHINA
| | - Naifang Hu
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences Qingdao Industrial Energy Storage Research Institute CHINA
| | - Chao Li
- Tianjin University of Technology Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials and Low Carbon Technologies, School of Materials Science and Engineering CHINA
| | - Jun Ma
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences Qingdao Industrial Energy Storage Research Institute CHINA
| | - Jianwei Zhang
- Tianjin University of Technology Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials and Low Carbon Technologies, School of Materials Science and Engineering CHINA
| | - Yuan Yang
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences Qingdao Industrial Energy Storage Research Institute CHINA
| | - Deye Sun
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences Qingdao Industrial Energy Storage Research Institute CHINA
| | - Bangxun Yin
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences Qingdao Industrial Energy Storage Research Institute CHINA
| | - Guanglei Cui
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences Department of Energy Science and Energy Technology Songling Road, 189 266101 Qingdao City CHINA
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17
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Seki T, Khare K, Murakami YO, Toyama S, Sánchez-Santolino G, Sasaki H, Findlay SD, Petersen TC, Ikuhara Y, Shibata N. Linear imaging theory for differential phase contrast and other phase imaging modes in scanning transmission electron microscopy. Ultramicroscopy 2022; 240:113580. [DOI: 10.1016/j.ultramic.2022.113580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/13/2022] [Accepted: 06/21/2022] [Indexed: 11/17/2022]
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18
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Quantitative electric field mapping in semiconductor heterostructures via tilt-scan averaged DPC STEM. Ultramicroscopy 2022; 238:113538. [DOI: 10.1016/j.ultramic.2022.113538] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/14/2022] [Accepted: 04/23/2022] [Indexed: 11/23/2022]
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19
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STEM Tools for Semiconductor Characterization: Beyond High-Resolution Imaging. NANOMATERIALS 2022; 12:nano12030337. [PMID: 35159686 PMCID: PMC8840450 DOI: 10.3390/nano12030337] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 12/10/2022]
Abstract
The smart engineering of novel semiconductor devices relies on the development of optimized functional materials suitable for the design of improved systems with advanced capabilities aside from better efficiencies. Thereby, the characterization of these materials at the highest level attainable is crucial for leading a proper understanding of their working principle. Due to the striking effect of atomic features on the behavior of semiconductor quantum- and nanostructures, scanning transmission electron microscopy (STEM) tools have been broadly employed for their characterization. Indeed, STEM provides a manifold characterization tool achieving insights on, not only the atomic structure and chemical composition of the analyzed materials, but also probing internal electric fields, plasmonic oscillations, light emission, band gap determination, electric field measurements, and many other properties. The emergence of new detectors and novel instrumental designs allowing the simultaneous collection of several signals render the perfect playground for the development of highly customized experiments specifically designed for the required analyses. This paper presents some of the most useful STEM techniques and several strategies and methodologies applied to address the specific analysis on semiconductors. STEM imaging, spectroscopies, 4D-STEM (in particular DPC), and in situ STEM are summarized, showing their potential use for the characterization of semiconductor nanostructured materials through recent reported studies.
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20
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Kohno Y, Nakamura A, Morishita S, Shibata N. Development of Tilt-Scan System for Differential Phase Contrast Scanning Transmission Electron Microscopy. Microscopy (Oxf) 2022; 71:111-116. [PMID: 35032164 PMCID: PMC8973405 DOI: 10.1093/jmicro/dfac002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 11/25/2022] Open
Abstract
Differential phase contrast (DPC) scanning transmission electron microscopy can directly visualize electromagnetic fields inside a specimen. However, their image contrast is not only sensitive to the electromagnetic fields in the sample, but also the changes in diffraction conditions such as sample bends or thickness changes. These additional contrasts are called diffraction contrasts, and sometimes make it difficult to extract pure electromagnetic field information from the experimental DPC images. In this study, we developed a beam scan system that can acquire many DPC images from the same sample region with arbitrarily varying incident beam tilt angles to the sample. Then, these images are precisely averaged to form tilt-scan averaged DPC images. It is shown that the diffraction contrast can be effectively reduced in the tilt-scan averaged DPC images.
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Affiliation(s)
- Yuji Kohno
- *To whom correspondence should be addressed. E-mail:
| | - Akiho Nakamura
- EM Research and Development Department 2, JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558, Japan
| | - Shigeyuki Morishita
- EM Research and Development Department 2, JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558, Japan
| | - Naoya Shibata
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Yayoi 2-11-16, Bunkyo-ku, Tokyo 113-8656, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
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21
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Kalinin SV, Ziatdinov M, Hinkle J, Jesse S, Ghosh A, Kelley KP, Lupini AR, Sumpter BG, Vasudevan RK. Automated and Autonomous Experiments in Electron and Scanning Probe Microscopy. ACS NANO 2021; 15:12604-12627. [PMID: 34269558 DOI: 10.1021/acsnano.1c02104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Machine learning and artificial intelligence (ML/AI) are rapidly becoming an indispensable part of physics research, with domain applications ranging from theory and materials prediction to high-throughput data analysis. In parallel, the recent successes in applying ML/AI methods for autonomous systems from robotics to self-driving cars to organic and inorganic synthesis are generating enthusiasm for the potential of these techniques to enable automated and autonomous experiments (AE) in imaging. Here, we aim to analyze the major pathways toward AE in imaging methods with sequential image formation mechanisms, focusing on scanning probe microscopy (SPM) and (scanning) transmission electron microscopy ((S)TEM). We argue that automated experiments should necessarily be discussed in a broader context of the general domain knowledge that both informs the experiment and is increased as the result of the experiment. As such, this analysis should explore the human and ML/AI roles prior to and during the experiment and consider the latencies, biases, and prior knowledge of the decision-making process. Similarly, such discussion should include the limitations of the existing imaging systems, including intrinsic latencies, non-idealities, and drifts comprising both correctable and stochastic components. We further pose that the role of the AE in microscopy is not the exclusion of human operators (as is the case for autonomous driving), but rather automation of routine operations such as microscope tuning, etc., prior to the experiment, and conversion of low latency decision making processes on the time scale spanning from image acquisition to human-level high-order experiment planning. Overall, we argue that ML/AI can dramatically alter the (S)TEM and SPM fields; however, this process is likely to be highly nontrivial and initiated by combined human-ML workflows and will bring challenges both from the microscope and ML/AI sides. At the same time, these methods will enable opportunities and paradigms for scientific discovery and nanostructure fabrication.
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22
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Savitzky BH, Zeltmann SE, Hughes LA, Brown HG, Zhao S, Pelz PM, Pekin TC, Barnard ES, Donohue J, Rangel DaCosta L, Kennedy E, Xie Y, Janish MT, Schneider MM, Herring P, Gopal C, Anapolsky A, Dhall R, Bustillo KC, Ercius P, Scott MC, Ciston J, Minor AM, Ophus C. py4DSTEM: A Software Package for Four-Dimensional Scanning Transmission Electron Microscopy Data Analysis. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:712-743. [PMID: 34018475 DOI: 10.1017/s1431927621000477] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Scanning transmission electron microscopy (STEM) allows for imaging, diffraction, and spectroscopy of materials on length scales ranging from microns to atoms. By using a high-speed, direct electron detector, it is now possible to record a full two-dimensional (2D) image of the diffracted electron beam at each probe position, typically a 2D grid of probe positions. These 4D-STEM datasets are rich in information, including signatures of the local structure, orientation, deformation, electromagnetic fields, and other sample-dependent properties. However, extracting this information requires complex analysis pipelines that include data wrangling, calibration, analysis, and visualization, all while maintaining robustness against imaging distortions and artifacts. In this paper, we present py4DSTEM, an analysis toolkit for measuring material properties from 4D-STEM datasets, written in the Python language and released with an open-source license. We describe the algorithmic steps for dataset calibration and various 4D-STEM property measurements in detail and present results from several experimental datasets. We also implement a simple and universal file format appropriate for electron microscopy data in py4DSTEM, which uses the open-source HDF5 standard. We hope this tool will benefit the research community and help improve the standards for data and computational methods in electron microscopy, and we invite the community to contribute to this ongoing project.
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Affiliation(s)
- Benjamin H Savitzky
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Steven E Zeltmann
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Lauren A Hughes
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Hamish G Brown
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Shiteng Zhao
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Philipp M Pelz
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Thomas C Pekin
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489Berlin, Germany
| | - Edward S Barnard
- Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Jennifer Donohue
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Luis Rangel DaCosta
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI48109, USA
| | - Ellis Kennedy
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Yujun Xie
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | | | | | | | | | | | - Rohan Dhall
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Karen C Bustillo
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Peter Ercius
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Mary C Scott
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Jim Ciston
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Andrew M Minor
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Colin Ophus
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
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23
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Xie L, He D, He J. SnSe, the rising star thermoelectric material: a new paradigm in atomic blocks, building intriguing physical properties. MATERIALS HORIZONS 2021; 8:1847-1865. [PMID: 34846469 DOI: 10.1039/d1mh00091h] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Thermoelectric (TE) materials, which enable direct energy conversion between waste heat and electricity, have witnessed enormous and exciting developments over last several decades due to innovative breakthroughs both in materials and the synergistic optimization of structures and properties. Among the promising state-of-the-art materials for next-generation thermoelectrics, tin selenide (SnSe) has attracted rapidly growing research interest for its high TE performance and the intrinsic layered structure that leads to strong anisotropy. Moreover, complex interactions between lattice, charge, and orbital degrees of freedom in SnSe make up a large phase space for the optimization of its TE properties via the simultaneous tuning of structural and chemical features. Various techniques, especially advanced electron microscopy (AEM), have been devoted to exploring these critical multidiscipline correlations between TE properties and microstructures. In this review, we first focus on the intrinsic layered structure as well as the extrinsic structural "imperfectness" of various dimensions in SnSe as studied by AEM. Based on these characterization results, we give a comprehensive discussion on the current understanding of the structure-property relationship. We then point out the challenges and opportunities as provided by modern AEM techniques toward a deeper knowledge of SnSe based on electronic structures and lattice dynamics at the nanometer or even atomic scale, for example, the measurements of local charge and electric field distribution, phonon vibrations, bandgap, valence state, temperature, and resultant TE effects.
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Affiliation(s)
- Lin Xie
- Shenzhen Key Laboratory of Thermoelectric Materials and Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China.
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24
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4D-STEM at interfaces to GaN: Centre-of-mass approach & NBED-disc detection. Ultramicroscopy 2021; 228:113321. [PMID: 34175788 DOI: 10.1016/j.ultramic.2021.113321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/12/2021] [Accepted: 05/18/2021] [Indexed: 11/23/2022]
Abstract
4D-scanning transmission electron microscopy (4D-STEM) can be used to measure electric fields such as atomic fields or polarization-induced electric fields in crystal heterostructures. The paper focuses on effects occurring in 4D-STEM at interfaces, where two model systems are used: an AlN/GaN nanowire superlattice as well as a GaN/vacuum interface. Two different methods are applied: First, we employ the centre-of mass (COM) technique which uses the average momentum transfer evaluated from the intensity distribution in the diffraction pattern. Second, we measure the shift of the undiffracted disc (disc-detection method) in nano-beam electron diffraction (NBED). Both methods are applied to experimental and simulated 4D-STEM data sets. We find for both techniques distinct variations in the momentum transfer at interfaces between materials: In both model systems, peaks occur at the interfaces and we investigate possible sources and routes of interpretation. In case of the AlN/GaN superlattice, the COM and disc-detection methods are used to measure internal polarization-induced electric fields and we observed a reduction of the measured fields with increasing specimen thickness.
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25
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Pöllath S, Schwarzhuber F, Zweck J. The differential phase contrast uncertainty relation: Connection between electron dose and field resolution. Ultramicroscopy 2021; 228:113342. [PMID: 34171792 DOI: 10.1016/j.ultramic.2021.113342] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/31/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
Differential phase contrast (DPC) microscopy is a STEM imaging technique, which is used to measure magnetic and electric fields of mesoscopic and nanoscopic dimensions, i.e. interatomic distances (Chapman et al. 1978; Chapman et al. 1981; Chapman, 1984; Chapman et al. 1985; Chapman et al. 1997; Lohr et al. 2012; Shibata et al. 2015; Bauer et al. 2014; Carvalho et al. 2016; Lohr et al. 2016; Mueller-Caspary et al. 2019a,2019b; Mueller-Caspary et al. 2018; Mueller-Caspary et al. 2017; Mueller-Caspary et al. 2014; Winkler et al. 2020; Toyama et al. 2020). In this paper we will demonstrate that the electron dose per pixel deposited on the specimen is decisive to the precision and resolution of measurements of a field's local strength. Relations are given which connect a given electron dose per pixel to the fundamentally achievable precision to which the specimen's interaction with the electrons may be determined, taking into account quantum mechanical considerations. Vice versa, given a certain required precision, the required dose per pixel can be easily predicted for reliable measurements of a desired property. First, these relations are given for the case of a continuous, i.e. non-pixelated, detector followed by simulations which show that the same relations hold for pixelated detectors. Then, the achievable precision for detectors with different pixel counts in combination with different camera lengths is discussed and the maximum measurable field amplitude per set-up is determined. Finally, the effect of inhomogeneities within the diffraction disk is discussed and possible deviations from the derived relations are considered. We also demonstrate that Heisenberg's uncertainty relation determines the possible field resolution in differential phase contrast microscopy, and that the achievable local field resolution is a function of the applied electron dose per pixel.
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Affiliation(s)
- Simon Pöllath
- Physics Faculty, University of Regensburg, 93040, Regensburg, Germany
| | | | - Josef Zweck
- Physics Faculty, University of Regensburg, 93040, Regensburg, Germany.
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26
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Huang Q, Chen Z, Cabral MJ, Wang F, Zhang S, Li F, Li Y, Ringer SP, Luo H, Mai YW, Liao X. Direct observation of nanoscale dynamics of ferroelectric degradation. Nat Commun 2021; 12:2095. [PMID: 33828086 PMCID: PMC8027400 DOI: 10.1038/s41467-021-22355-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/11/2021] [Indexed: 02/01/2023] Open
Abstract
Failure of polarization reversal, i.e., ferroelectric degradation, induced by cyclic electric loadings in ferroelectric materials, has been a long-standing challenge that negatively impacts the application of ferroelectrics in devices where reliability is critical. It is generally believed that space charges or injected charges dominate the ferroelectric degradation. However, the physics behind the phenomenon remains unclear. Here, using in-situ biasing transmission electron microscopy, we discover change of charge distribution in thin ferroelectrics during cyclic electric loadings. Charge accumulation at domain walls is the main reason of the formation of c domains, which are less responsive to the applied electric field. The rapid growth of the frozen c domains leads to the ferroelectric degradation. This finding gives insights into the nature of ferroelectric degradation in nanodevices, and reveals the role of the injected charges in polarization reversal.
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Affiliation(s)
- Qianwei Huang
- grid.1013.30000 0004 1936 834XSchool of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW Australia
| | - Zibin Chen
- grid.1013.30000 0004 1936 834XSchool of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW Australia
| | - Matthew J. Cabral
- grid.1013.30000 0004 1936 834XSchool of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW Australia
| | - Feifei Wang
- grid.412531.00000 0001 0701 1077Key Laboratory of Optoelectronic Material and Device, Department of Physics, Shanghai Normal University, Shanghai, China
| | - Shujun Zhang
- grid.1007.60000 0004 0486 528XInstitute for Superconducting and Electronic Materials, Australian Institute of Innovative Materials, University of Wollongong, Wollongong, NSW Australia
| | - Fei Li
- grid.43169.390000 0001 0599 1243Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi’an Jiaotong University, Xi’an, China
| | - Yulan Li
- grid.451303.00000 0001 2218 3491Pacific Northwest National Laboratory, Richland, WA USA
| | - Simon P. Ringer
- grid.1013.30000 0004 1936 834XSchool of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW Australia
| | - Haosu Luo
- grid.9227.e0000000119573309Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China
| | - Yiu-Wing Mai
- grid.1013.30000 0004 1936 834XSchool of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW Australia
| | - Xiaozhou Liao
- grid.1013.30000 0004 1936 834XSchool of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW Australia
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27
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Min T, Choi W, Seo J, Han G, Song K, Ryu S, Lee H, Lee J, Eom K, Eom CB, Jeong HY, Kim YM, Lee J, Oh SH. Cooperative evolution of polar distortion and nonpolar rotation of oxygen octahedra in oxide heterostructures. SCIENCE ADVANCES 2021; 7:7/17/eabe9053. [PMID: 33883134 PMCID: PMC8059930 DOI: 10.1126/sciadv.abe9053] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/05/2021] [Indexed: 05/23/2023]
Abstract
Polarity discontinuity across LaAlO3/SrTiO3 (LAO/STO) heterostructures induces electronic reconstruction involving the formation of two-dimensional electron gas (2DEG) and structural distortions characterized by antiferrodistortive (AFD) rotation and ferroelectric (FE) distortion. We show that AFD and FE modes are cooperatively coupled in LAO/STO (111) heterostructures; they coexist below the critical thickness (t c) and disappear simultaneously above t c with the formation of 2DEG. Electron energy-loss spectroscopy and density functional theory (DFT) calculations provide direct evidence of oxygen vacancy (V O) formation at the LAO (111) surface, which acts as the source of 2DEG. Tracing the AFD rotation and FE distortion of LAO reveals that their evolution is strongly correlated with V O distribution. The present study demonstrates that AFD and FE modes in oxide heterostructures emerge as a consequence of interplay between misfit strain and polar field, and further that their combination can be tuned to competitive or cooperative coupling by changing the interface orientation.
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Affiliation(s)
- Taewon Min
- Department of Physics, Pusan National University, Busan 46241, Republic of Korea
| | - Wooseon Choi
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jinsol Seo
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Gyeongtak Han
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Kyung Song
- Materials Testing and Reliability Division, Korea Institute of Materials Science (KIMS), Changwon 51508, Republic of Korea
| | - Sangwoo Ryu
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hyungwoo Lee
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jungwoo Lee
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kitae Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Chang-Beom Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hu Young Jeong
- UNIST Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea.
| | - Jaekwang Lee
- Department of Physics, Pusan National University, Busan 46241, Republic of Korea.
| | - Sang Ho Oh
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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28
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ab initio description of bonding for transmission electron microscopy. Ultramicroscopy 2021; 231:113253. [PMID: 33773844 DOI: 10.1016/j.ultramic.2021.113253] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 02/12/2021] [Accepted: 02/20/2021] [Indexed: 01/10/2023]
Abstract
The simulation of transmission electron microscopy (TEM) images or diffraction patterns is often required to interpret their contrast and extract specimen features. This is especially true for high-resolution phase-contrast imaging of materials, but electron scattering simulations based on atomistic models are widely used in materials science and structural biology. Since electron scattering is dominated by the nuclear cores, the scattering potential is typically described by the widely applied independent atom model. This approximation is fast and fairly accurate, especially for scanning TEM (STEM) annular dark-field contrast, but it completely neglects valence bonding and its effect on the transmitting electrons. However, an emerging trend in electron microscopy is to use new instrumentation and methods to extract the maximum amount of information from each electron. This is evident in the increasing popularity of techniques such as 4D-STEM combined with ptychography in materials science, and cryogenic microcrystal electron diffraction in structural biology, where subtle differences in the scattering potential may be both measurable and contain additional insights. Thus, there is increasing interest in electron scattering simulations based on electrostatic potentials obtained from first principles, mainly via density functional theory, which was previously mainly required for holography. In this Review, we discuss the motivation and basis for these developments, survey the pioneering work that has been published thus far, and give our outlook for the future. We argue that a physically better justified ab initio description of the scattering potential is both useful and viable for an increasing number of systems, and we expect such simulations to steadily gain in popularity and importance.
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29
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Beyer A, Munde MS, Firoozabadi S, Heimes D, Grieb T, Rosenauer A, Müller-Caspary K, Volz K. Quantitative Characterization of Nanometer-Scale Electric Fields via Momentum-Resolved STEM. NANO LETTERS 2021; 21:2018-2025. [PMID: 33621104 DOI: 10.1021/acs.nanolett.0c04544] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Most of today's electronic devices, like solar cells and batteries, are based on nanometer-scale built-in electric fields. Accordingly, characterization of fields at such small scales has become an important task in the optimization of these devices. In this study, with GaAs-based p-n junctions as the example, key characteristics such as doping concentrations, polarity, and the depletion width are derived quantitatively using four-dimensional scanning transmission electron microscopy (4DSTEM). The built-in electric fields are determined by the shift they introduce to the center-of-mass of electron diffraction patterns at subnanometer spatial resolution. The method is applied successfully to characterize two p-n junctions with different doping concentrations. This highlights the potential of this method to directly visualize intentional or unintentional nanoscale electric fields in real-life devices, e.g., batteries, transistors, and solar cells.
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Affiliation(s)
- Andreas Beyer
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Manveer Singh Munde
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Saleh Firoozabadi
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Damien Heimes
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Tim Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Knut Müller-Caspary
- Ernst Ruska-Center for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, RWTH Aachen University, II. Institute of Physics, Otto-Blumenthal-Straße, Aachen 52074, Germany
| | - Kerstin Volz
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
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30
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Reidy K, Varnavides G, Thomsen JD, Kumar A, Pham T, Blackburn AM, Anikeeva P, Narang P, LeBeau JM, Ross FM. Direct imaging and electronic structure modulation of moiré superlattices at the 2D/3D interface. Nat Commun 2021; 12:1290. [PMID: 33637704 PMCID: PMC7910301 DOI: 10.1038/s41467-021-21363-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 01/20/2021] [Indexed: 01/31/2023] Open
Abstract
The atomic structure at the interface between two-dimensional (2D) and three-dimensional (3D) materials influences properties such as contact resistance, photo-response, and high-frequency electrical performance. Moiré engineering is yet to be utilized for tailoring this 2D/3D interface, despite its success in enabling correlated physics at 2D/2D interfaces. Using epitaxially aligned MoS2/Au{111} as a model system, we demonstrate the use of advanced scanning transmission electron microscopy (STEM) combined with a geometric convolution technique in imaging the crystallographic 32 Å moiré pattern at the 2D/3D interface. This moiré period is often hidden in conventional electron microscopy, where the Au structure is seen in projection. We show, via ab initio electronic structure calculations, that charge density is modulated according to the moiré period, illustrating the potential for (opto-)electronic moiré engineering at the 2D/3D interface. Our work presents a general pathway to directly image periodic modulation at interfaces using this combination of emerging microscopy techniques.
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Affiliation(s)
- Kate Reidy
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Georgios Varnavides
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Joachim Dahl Thomsen
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Abinash Kumar
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Thang Pham
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Arthur M Blackburn
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
| | - Polina Anikeeva
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Prineha Narang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - James M LeBeau
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA.
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31
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Seki T, Ikuhara Y, Shibata N. Toward quantitative electromagnetic field imaging by differential-phase-contrast scanning transmission electron microscopy. Microscopy (Oxf) 2021; 70:148-160. [PMID: 33150939 DOI: 10.1093/jmicro/dfaa065] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/26/2020] [Accepted: 10/30/2020] [Indexed: 11/14/2022] Open
Abstract
Differential-phase-contrast scanning transmission electron microscopy (DPC STEM) is a technique to directly visualize local electromagnetic field distribution inside materials and devices at very high spatial resolution. Owing to the recent progress in the development of high-speed segmented and pixelated detectors, DPC STEM now constitutes one of the major imaging modes in modern aberration-corrected STEM. While qualitative imaging of electromagnetic fields by DPC STEM is readily possible, quantitative imaging by DPC STEM is still under development because of the several fundamental issues inherent in the technique. In this report, we review the current status and future prospects of DPC STEM for quantitative electromagnetic field imaging from atomic scale to mesoscopic scale.
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Affiliation(s)
- Takehito Seki
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Yayoi 2-11-16, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yuichi Ikuhara
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Yayoi 2-11-16, Bunkyo-ku, Tokyo 113-8656, Japan.,Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
| | - Naoya Shibata
- Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Yayoi 2-11-16, Bunkyo-ku, Tokyo 113-8656, Japan.,Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan.,Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan
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32
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Isobe K, Okino R, Hanamura K. Spectral absorptance of a metal-semiconductor-metal thin-multilayer structured thermophotovoltaic cell. OPTICS EXPRESS 2020; 28:40099-40111. [PMID: 33379543 DOI: 10.1364/oe.410828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/22/2020] [Indexed: 06/12/2023]
Abstract
Spectral absorptance of a metal-semiconductor-metal (MSM) thin-multilayer structured thermo-photovoltaic cell was experimentally investigated. A MSM consists of a thin GaSb-semiconductor sandwiched between a top fishnet-type electrode and a flat backside electrode made of gold. A thin GaSb layer was grown on a substrate made of InAs using molecular beam epitaxy, and then all of the InAs substrate was removed using wet etching. The GaSb film was bonded on a surface of gold, which was sputtered on a Si substrate, using a van der Waals bonding method. The top fishnet-type electrode was made using electron beam lithography and a lift-off process. In the case of a 115 nm thick GaSb layer and a square fishnet aperture of a 300 nm × 310 nm size, the spectral absorptance of MSM reached a local peak (95%) at a wavelength of 1.66 µm, which is similar to spectra predicted by numerical simulation. Moreover, the equivalent resonance cavity model and LC circuit model functioned well to indicate the wavelength of several distinct peaks of absorptance.
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33
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Cooper D, Boureau V, Even A, Barbier F, Dussaigne A. Determination of the internal piezoelectric potentials and indium concentration in InGaN based quantum wells grown on relaxed InGaN pseudo-substrates by off-axis electron holography. NANOTECHNOLOGY 2020; 31:475705. [PMID: 32764191 DOI: 10.1088/1361-6528/abad5f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Micro light emitting diodes have been grown by metal organic vapor phase epitaxy on standard GaN and partly relaxed InGaNOS substrates with the purpose of incorporating higher concentrations of indium for identical growth conditions. Green emission has been demonstrated at wavelengths of 500 nm for the GaN template and 525 and 549 nm for the InGaNOS substrates, respectively. The structure, deformation, indium concentration and piezoelectric potentials have been measured with nm-scale spatial resolution in the same specimens by transmission electron microscopy. We show by off-axis electron holography that the piezoelectric potential and information about the indium concentration from the mean inner potential are obtained simultaneously. By separating the components using a model, we show that for higher concentrations of indium in the quantum wells (QWs) grown on InGaNOS substrates, the piezoelectric potentials are reduced. The measurements of the indium concentrations by electron holography have been verified by combining energy dispersive x-ray spectrometry, x-ray diffraction and from the tensile deformation made by precession electron diffraction. A discussion of the limitations of these advanced aberration-corrected transmission electron microscopy techniques when applied to nm-scale QW structures is given.
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Affiliation(s)
- D Cooper
- University of Grenoble-Alpes, CEA, LETI, Minatec Campus, F-38054, Grenoble, France
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34
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Wang L, Xie R, Chen B, Yu X, Ma J, Li C, Hu Z, Sun X, Xu C, Dong S, Chan TS, Luo J, Cui G, Chen L. In-situ visualization of the space-charge-layer effect on interfacial lithium-ion transport in all-solid-state batteries. Nat Commun 2020; 11:5889. [PMID: 33208730 PMCID: PMC7674427 DOI: 10.1038/s41467-020-19726-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 10/23/2020] [Indexed: 11/09/2022] Open
Abstract
The space charge layer (SCL) is generally considered one of the origins of the sluggish interfacial lithium-ion transport in all-solid-state lithium-ion batteries (ASSLIBs). However, in-situ visualization of the SCL effect on the interfacial lithium-ion transport in sulfide-based ASSLIBs is still a great challenge. Here, we directly observe the electrode/electrolyte interface lithium-ion accumulation resulting from the SCL by investigating the net-charge-density distribution across the high-voltage LiCoO2/argyrodite Li6PS5Cl interface using the in-situ differential phase contrast scanning transmission electron microscopy (DPC-STEM) technique. Moreover, we further demonstrate a built-in electric field and chemical potential coupling strategy to reduce the SCL formation and boost lithium-ion transport across the electrode/electrolyte interface by the in-situ DPC-STEM technique and finite element method simulations. Our findings will strikingly advance the fundamental scientific understanding of the SCL mechanism in ASSLIBs and shed light on rational electrode/electrolyte interface design for high-rate performance ASSLIBs.
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Affiliation(s)
- Longlong Wang
- Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Ruicong Xie
- Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin, 300384, China
| | - Bingbing Chen
- School of Energy Science and Engineering, Nanjing Tech University, Nanjing, 210000, China
| | - Xinrun Yu
- Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Jun Ma
- Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
| | - Chao Li
- Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin, 300384, China.
| | - Zhiwei Hu
- Max Plank Institute for Chemical Physics of Solids, Nothnitzer Strasse 40, D-01187, Dresden, Germany
| | - Xingwei Sun
- Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Chengjun Xu
- School of Energy Science and Engineering, Nanjing Tech University, Nanjing, 210000, China
| | - Shanmu Dong
- Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Ting-Shan Chan
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan, 30076, Republic of China
| | - Jun Luo
- Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin, 300384, China.
| | - Guanglei Cui
- Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China. .,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Liquan Chen
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
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35
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Bürger J, Riedl T, Lindner JKN. Influence of lens aberrations, specimen thickness and tilt on differential phase contrast STEM images. Ultramicroscopy 2020; 219:113118. [PMID: 33126186 DOI: 10.1016/j.ultramic.2020.113118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/30/2020] [Accepted: 09/13/2020] [Indexed: 12/01/2022]
Abstract
Differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM) allows for measuring electric and magnetic fields in solids on scales ranging from picometres to micrometres. The DPC technique mainly uses the direct beam, which is deflected by the electric and magnetic fields of the specimen and measured with a beam position sensitive detector. The beam deflection and thus the DPC signal is strongly influenced by specimen thickness, specimen tilt and lens aberrations. Understanding these influences is critical for a solid interpretation and quantification of contrasts in DPC images. To this end, the present study employs DPC-STEM image simulations of SrTiO3 [001] at atomic resolution to analyse the influence of lens aberrations, specimen tilt and thickness and also to give a guideline for the detection of parameters affecting the contrast by performing an analysis of associated scattergrams. Simulations are obtained using the multislice algorithm implemented in the Dr. Probe software with conditions corresponding to a JEOL ARM200F microscope equipped with an octa-segmented annular detector, but results should be similar for other microscopes. Simulations show that due to a non-rigid shift of the detected intensity distribution correct values of projected potentials of specimens thicker than one unit-cell cannot be determined. Regarding the impact of residual lens aberrations, it is found that the shape of the lens aberration phase function determines the symmetry and features in the DPC image. Specimen tilt leads to an elongation of features perpendicular to the tilt axis. The results are confirmed by comparing simulated with experimental DPC images of Si [110] yielding good agreement. Overall, a high sensitivity of DPC-STEM imaging to lens aberrations, specimen tilt and diffraction effects is evidenced.
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Affiliation(s)
- Julius Bürger
- Paderborn University, Department of Physics, Warburger Str. 100, 33098 Paderborn, Germany; Center for Optoelectronics and Photonics Paderborn CeOPP, Paderborn University, 33098 Paderborn, Germany; Institute of Lightweight Design with Hybrid Materials ILH, Paderborn University, 33098 Paderborn, Germany.
| | - Thomas Riedl
- Paderborn University, Department of Physics, Warburger Str. 100, 33098 Paderborn, Germany; Center for Optoelectronics and Photonics Paderborn CeOPP, Paderborn University, 33098 Paderborn, Germany; Institute of Lightweight Design with Hybrid Materials ILH, Paderborn University, 33098 Paderborn, Germany.
| | - Jörg K N Lindner
- Paderborn University, Department of Physics, Warburger Str. 100, 33098 Paderborn, Germany; Center for Optoelectronics and Photonics Paderborn CeOPP, Paderborn University, 33098 Paderborn, Germany; Institute of Lightweight Design with Hybrid Materials ILH, Paderborn University, 33098 Paderborn, Germany.
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36
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Murakami YO, Seki T, Kinoshita A, Shoji T, Ikuhara Y, Shibata N. Magnetic-structure imaging in polycrystalline materials by specimen-tilt series averaged DPC STEM. ACTA ACUST UNITED AC 2020; 69:312-320. [PMID: 32455425 DOI: 10.1093/jmicro/dfaa029] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 11/15/2022]
Abstract
Differential phase contrast (DPC) imaging in scanning transmission electron microscopy is a technique to visualize electromagnetic field distribution inside specimens at high spatial resolution. However, diffraction contrast strongly hampers electromagnetic contrast in DPC images especially in polycrystalline samples. In this paper, we develop an imaging technique to effectively suppress diffraction contrast in DPC images. It is shown that a magnetic structure in a Nd-Fe-B permanent magnet was clearly visualized by averaging 64 DPC images with various specimen-tilt conditions. This is because the diffraction contrast in DPC images sensitively and randomly varies with crystal orientation and thus almost vanishes by averaging specimen-tilt image series. We further investigated two types of residual diffraction contrast in the tilt-series averaged DPC images: weak contrast inside grains and strong contrast at grain boundaries. We found that the former can be suppressed by averaging more DPC images, whereas the latter can be suppressed by the tilt-series averaging with wider range of specimen tilt. The tilt-series averaging method enables DPC to visualize electromagnetic structures even inside polycrystalline materials.
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Affiliation(s)
- Yoshiki O Murakami
- Institute of Engineering Innovation, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takehito Seki
- Institute of Engineering Innovation, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Akihito Kinoshita
- Advanced Material Engineering Division, Toyota Motor Corporation, 1200, Mishuku, Susono, Shizuoka 410-1193, Japan
| | - Tetsuya Shoji
- Advanced Material Engineering Division, Toyota Motor Corporation, 1200, Mishuku, Susono, Shizuoka 410-1193, Japan
| | - Yuichi Ikuhara
- Nano Structures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Matsuno, Atsuta-ku, Nagoya 456-8587, Japan
| | - Naoya Shibata
- Institute of Engineering Innovation, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
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37
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Inamoto S, Shimomura S, Otsuka Y. Electrostatic potential imaging of phase-separated structures in organic materials via differential phase contrast scanning transmission electron microscopy. ACTA ACUST UNITED AC 2020; 69:304-311. [PMID: 32453389 DOI: 10.1093/jmicro/dfaa027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 11/13/2022]
Abstract
Electron staining is generally performed prior to observing organic materials via transmission electron microscopy (TEM) to enhance image contrast. However, electron staining can deteriorate organic materials. Here, we demonstrate electrostatic potential imaging of organic materials via differential phase contrast (DPC) scanning transmission electron microscopy (STEM) without electron staining. Electrostatic potential imaging drastically increases the contrast between different materials. Phase-separated structures in a poly (3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend that are impossible to observe using conventional STEM are clearly visualized. Furthermore, annealing behavior of the phase-separated structures is directly observed. The morphological transformations in the samples are consistent with their physical parameters, including their glass transition and melting temperatures. Our results indicate that electrostatic potential imaging is highly effective for observing organic materials.
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Affiliation(s)
- Shin Inamoto
- Morphological Research Laboratory, Toray Research Center, Inc., 3-7, Sonoyama 3-chome, Otsu, Shiga 520-8567, Japan
| | - Satoru Shimomura
- Advanced Materials Research Laboratories, Toray Industries, Inc., 2-1, Sonoyama 3-chome, Otsu, Shiga 520-0842, Japan
| | - Yuji Otsuka
- Morphological Research Laboratory, Toray Research Center, Inc., 3-7, Sonoyama 3-chome, Otsu, Shiga 520-8567, Japan
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38
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Yun S, Song K, Chu K, Hwang SY, Kim GY, Seo J, Woo CS, Choi SY, Yang CH. Flexopiezoelectricity at ferroelastic domain walls in WO 3 films. Nat Commun 2020; 11:4898. [PMID: 32994411 PMCID: PMC7524836 DOI: 10.1038/s41467-020-18644-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 09/03/2020] [Indexed: 11/18/2022] Open
Abstract
The emergence of a domain wall property that is forbidden by symmetry in bulk can offer unforeseen opportunities for nanoscale low-dimensional functionalities in ferroic materials. Here, we report that the piezoelectric response is greatly enhanced in the ferroelastic domain walls of centrosymmetric tungsten trioxide thin films due to a large strain gradient of 106 m−1, which exists over a rather wide width (~20 nm) of the wall. The interrelationship between the strain gradient, electric polarity, and the electromechanical property is scrutinized by detecting of the lattice distortion using atomic scale strain analysis, and also by detecting the depolarized electric field using differential phase contrast technique. We further demonstrate that the domain walls can be manipulated and aligned in specific directions deterministically using a scanning tip, which produces a surficial strain gradient. Our findings provide the comprehensive observation of a flexopiezoelectric phenomenon that is artificially controlled by externally induced strain gradients. Observation of a strain-gradient-induced piezoresponse at domain walls remains a challenge. Here, the authors find the piezoelectric response to be enhanced in the ferroelastic domain walls of centrosymmetric tungsten trioxide thin films due to a large strain gradient over a wide width of the wall.
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Affiliation(s)
- Shinhee Yun
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Kyung Song
- Department of Materials Analysis and Evaluation, Korea Institute of Materials Science (KIMS), Changwon, 51508, Republic of Korea
| | - Kanghyun Chu
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Group for Ferroelectrics and Functional Oxides, Institute of Materials, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Soo-Yoon Hwang
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Gi-Yeop Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jeongdae Seo
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Chang-Su Woo
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
| | - Chan-Ho Yang
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea. .,KAIST Institute for the NanoCentury, KAIST, Daejeon, 34141, Republic of Korea.
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39
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Mawson T, Nakamura A, Petersen TC, Shibata N, Sasaki H, Paganin DM, Morgan MJ, Findlay SD. Suppressing dynamical diffraction artefacts in differential phase contrast scanning transmission electron microscopy of long-range electromagnetic fields via precession. Ultramicroscopy 2020; 219:113097. [PMID: 32905857 DOI: 10.1016/j.ultramic.2020.113097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/14/2020] [Accepted: 08/26/2020] [Indexed: 11/18/2022]
Abstract
It is well known that dynamical diffraction varies with changes in sample thickness and local crystal orientation (due to sample bending). In differential phase contrast scanning transmission electron microscopy (DPC-STEM), this can produce contrast comparable to that arising from the long-range electromagnetic fields probed by this technique. Through simulation we explore the scale of these dynamical diffraction artefacts and introduce a metric for the magnitude of their contribution to the contrast. We show that precession over an angular range of a few milliradian can suppress this contribution to the contrast by one-to-two orders of magnitude. Our exploration centres around a case study of GaAs near the [011] zone-axis orientation using a probe-forming aperture semiangle on the order of 0.1 mrad at 300 keV, but the trends found and methodology used are expected to apply more generally.
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Affiliation(s)
- T Mawson
- School of Physics and Astronomy, Monash University, Victoria 3800, Australia
| | - A Nakamura
- JEOL Ltd., Akishima, Tokyo 196-8558, Japan
| | - T C Petersen
- School of Physics and Astronomy, Monash University, Victoria 3800, Australia; Monash Centre for Electron Microscopy, Monash University, Victoria 3800, Australia
| | - N Shibata
- Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
| | - H Sasaki
- Furukawa Electric Ltd., Yokohama 220-0073, Japan
| | - D M Paganin
- School of Physics and Astronomy, Monash University, Victoria 3800, Australia
| | - M J Morgan
- School of Physics and Astronomy, Monash University, Victoria 3800, Australia
| | - S D Findlay
- School of Physics and Astronomy, Monash University, Victoria 3800, Australia.
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40
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Skewed electronic band structure induced by electric polarization in ferroelectric BaTiO 3. Sci Rep 2020; 10:10702. [PMID: 32612212 PMCID: PMC7329818 DOI: 10.1038/s41598-020-67651-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 06/08/2020] [Indexed: 11/09/2022] Open
Abstract
Skewed band structures have been empirically described in ferroelectric materials to explain the functioning of recently developed ferroelectric tunneling junction (FTJs). Nonvolatile ferroelectric random access memory (FeRAM) and the artificial neural network device based on the FTJ system are rapidly developing. However, because the actual ferroelectric band structure has not been elucidated, precise designing of devices has to be advanced through appropriate heuristics. Here, we perform angle-resolved hard X-ray photoemission spectroscopy of ferroelectric BaTiO3 thin films for the direct observation of ferroelectric band skewing structure as the depth profiles of atomic orbitals. The depth-resolved electronic band structure consists of three depth regions: a potential slope along the electric polarization in the core, the surface and interface exhibiting slight changes. We also demonstrate that the direction of the energy shift is controlled by the polarization reversal. In the ferroelectric skewed band structure, we found that the difference in energy shifts of the atomic orbitals is correlated with the atomic configuration of the soft phonon mode reflecting the Born effective charges. These findings lead to a better understanding of the origin of electric polarization.
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41
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Zhang C, Feng Y, Han Z, Gao S, Wang M, Wang P. Electrochemical and Structural Analysis in All-Solid-State Lithium Batteries by Analytical Electron Microscopy: Progress and Perspectives. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1903747. [PMID: 31660670 DOI: 10.1002/adma.201903747] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/14/2019] [Indexed: 06/10/2023]
Abstract
Advanced scanning transmission electron microscopy (STEM) and its associated instruments have made significant contributions to the characterization of all-solid-state (ASS) Li batteries, as these tools provide localized information on the structure, morphology, chemistry, and electronic state of electrodes, electrolytes, and their interfaces at the nano- and atomic scale. Furthermore, the rapid development of in situ techniques has enabled a deep understanding of interfacial dynamic behavior and heterogeneous characteristics during the cycling process. However, due to the beam-sensitive nature of light elements in the interphases, e.g., Li and O, thorough and reliable studies of the interfacial structure and chemistry at an ultrahigh spatial resolution without beam damage is still a formidable challenge. Herein, the following points are discussed: (1) the recent contributions of advanced STEM to the study of ASS Li batteries; (2) current challenges associated with using this method; and (3) potential opportunities for combining cryo-electron microscopy and the STEM phase contrast imaging techniques.
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Affiliation(s)
- Chunchen Zhang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yuzhang Feng
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zhen Han
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Si Gao
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Meiyu Wang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Peng Wang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
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42
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Toyama S, Seki T, Anada S, Sasaki H, Yamamoto K, Ikuhara Y, Shibata N. Quantitative electric field mapping of a p-n junction by DPC STEM. Ultramicroscopy 2020; 216:113033. [PMID: 32570133 DOI: 10.1016/j.ultramic.2020.113033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/09/2020] [Accepted: 05/24/2020] [Indexed: 10/24/2022]
Abstract
Local electromagnetic fields in a specimen is measured at high spatial resolutions using differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). According to previous studies, DPC signals can be quantified by measuring the center of mass of the diffraction pattern intensity and/or performing a deconvolution method based on a phase contrast transfer function (PCTF). However, when using a segmented detector, the field strength has been considerably underestimated for a very thick specimen. The main cause of the underestimation is assumed to be inelastic scattering, mainly bulk plasmon scattering. In this study, we develop a method to remove this inelastic scattering effect from segmented detector DPC signals by modifying the PCTF deconvolution method. Field quantification results using this new technique are compared with those using pixelated detector DPC and electron holography, and all results indicated good agreement within an error margin.
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Affiliation(s)
- Satoko Toyama
- Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan
| | - Takehito Seki
- Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan
| | - Satoshi Anada
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
| | - Hirokazu Sasaki
- Advanced Technologies R&D Laboratories, Furukawa Electric Co., Ltd., Yokohama 220-0073, Japan
| | - Kazuo Yamamoto
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
| | - Yuichi Ikuhara
- Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
| | - Naoya Shibata
- Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan.
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43
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Campanini M, Erni R, Rossell MD. Probing local order in multiferroics by transmission electron microscopy. PHYSICAL SCIENCES REVIEWS 2020. [DOI: 10.1515/psr-2019-0068] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The ongoing trend toward miniaturization has led to an increased interest in the magnetoelectric effect, which could yield entirely new device concepts, such as electric field-controlled magnetic data storage. As a result, much work is being devoted to developing new robust room temperature (RT) multiferroic materials that combine ferromagnetism and ferroelectricity. However, the development of new multiferroic devices has proved unexpectedly challenging. Thus, a better understanding of the properties of multiferroic thin films and the relation with their microstructure is required to help drive multiferroic devices toward technological application. This review covers in a concise manner advanced analytical imaging methods based on (scanning) transmission electron microscopy which can potentially be used to characterize complex multiferroic materials. It consists of a first broad introduction to the topic followed by a section describing the so-called phase-contrast methods, which can be used to map the polar and magnetic order in magnetoelectric multiferroics at different spatial length scales down to atomic resolution. Section 3 is devoted to electron nanodiffraction methods. These methods allow measuring local strains, identifying crystal defects and determining crystal structures, and thus offer important possibilities for the detailed structural characterization of multiferroics in the ultrathin regime or inserted in multilayers or superlattice architectures. Thereafter, in Section 4, methods are discussed which allow for analyzing local strain, whereas in Section 5 methods are addressed which allow for measuring local polarization effects on a length scale of individual unit cells. Here, it is shown that the ferroelectric polarization can be indirectly determined from the atomic displacements measured in atomic resolution images. Finally, a brief outlook is given on newly established methods to probe the behavior of ferroelectric and magnetic domains and nanostructures during in situ heating/electrical biasing experiments. These in situ methods are just about at the launch of becoming increasingly popular, particularly in the field of magnetoelectric multiferroics, and shall contribute significantly to understanding the relationship between the domain dynamics of multiferroics and the specific microstructure of the films providing important guidance to design new devices and to predict and mitigate failures.
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44
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Zachman MJ, Hachtel JA, Idrobo JC, Chi M. Emerging Electron Microscopy Techniques for Probing Functional Interfaces in Energy Materials. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902993] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Michael J. Zachman
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Jordan A. Hachtel
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
| | - Miaofang Chi
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
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45
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Zachman MJ, Hachtel JA, Idrobo JC, Chi M. Emerging Electron Microscopy Techniques for Probing Functional Interfaces in Energy Materials. Angew Chem Int Ed Engl 2019; 59:1384-1396. [PMID: 31081976 DOI: 10.1002/anie.201902993] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/01/2019] [Indexed: 11/10/2022]
Abstract
Interfaces play a fundamental role in many areas of chemistry. However, their localized nature requires characterization techniques with high spatial resolution in order to fully understand their structure and properties. State-of-the-art atomic resolution or in situ scanning transmission electron microscopy and electron energy-loss spectroscopy are indispensable tools for characterizing the local structure and chemistry of materials with single-atom resolution, but they are not able to measure many properties that dictate function, such as vibrational modes or charge transfer, and are limited to room-temperature samples containing no liquids. Here, we outline emerging electron microscopy techniques that are allowing these limitations to be overcome and highlight several recent studies that were enabled by these techniques. We then provide a vision for how these techniques can be paired with each other and with in situ methods to deliver new insights into the static and dynamic behavior of functional interfaces.
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Affiliation(s)
- Michael J Zachman
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Miaofang Chi
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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46
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Zhang Q, Hu G, de Boo GG, Rančić M, Johnson BC, McCallum JC, Du J, Sellars MJ, Yin C, Rogge S. Single Rare-Earth Ions as Atomic-Scale Probes in Ultrascaled Transistors. NANO LETTERS 2019; 19:5025-5030. [PMID: 31251075 DOI: 10.1021/acs.nanolett.9b01281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Continued scaling of semiconductor devices has driven information technology into vastly diverse applications. The performance of ultrascaled transistors is strongly influenced by local electric field and strain. As the size of these devices approaches fundamental limits, it is imperative to develop characterization techniques with nanometer resolution and three-dimensional (3D) mapping capabilities for device optimization. Here, we report on the use of single erbium (Er) ions as atomic probes for the electric field and strain in a silicon ultrascaled transistor. Stark shifts on the Er3+ spectra induced by both the overall electric field and the local charge environment are observed. Changes in strain smaller than 3 × 10-6 are detected, which is around 2 orders of magnitude more sensitive than the standard techniques used in the semiconductor industry. These results open new possibilities for 3D mapping of the local strain and electric field in the channel of ultrascaled transistors.
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Affiliation(s)
- Qi Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics , University of Science and Technology of China , Hefei 230026 , China
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics , University of New South Wales , Sydney , New South Wales 2052 , Australia
- CAS Key Laboratory of Microscale Magnetic Resonance , University of Science and Technology of China , Hefei 230026 , China
- Synergetic Innovation Center of Quantum Information and Quantum Physics , University of Science and Technology of China , Hefei 230026 , China
| | - Guangchong Hu
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics , University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Gabriele G de Boo
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics , University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Miloš Rančić
- Centre of Excellence for Quantum Computation and Communication Technology, Research School of Physics , Australian National University , Canberra , Australian Capital Territory 0200 , Australia
- Quantronics Group, SPEC, CEA Saclay , 91191 Gif-sur-Yvette Cedex , France
| | - Brett C Johnson
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics , University of Melbourne , Melbourne , Victoria 3010 , Australia
| | - Jeffrey C McCallum
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics , University of Melbourne , Melbourne , Victoria 3010 , Australia
| | - Jiangfeng Du
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics , University of Science and Technology of China , Hefei 230026 , China
- CAS Key Laboratory of Microscale Magnetic Resonance , University of Science and Technology of China , Hefei 230026 , China
- Synergetic Innovation Center of Quantum Information and Quantum Physics , University of Science and Technology of China , Hefei 230026 , China
| | - Matthew J Sellars
- Centre of Excellence for Quantum Computation and Communication Technology, Research School of Physics , Australian National University , Canberra , Australian Capital Territory 0200 , Australia
| | - Chunming Yin
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics , University of Science and Technology of China , Hefei 230026 , China
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics , University of New South Wales , Sydney , New South Wales 2052 , Australia
- CAS Key Laboratory of Microscale Magnetic Resonance , University of Science and Technology of China , Hefei 230026 , China
- Synergetic Innovation Center of Quantum Information and Quantum Physics , University of Science and Technology of China , Hefei 230026 , China
| | - Sven Rogge
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics , University of New South Wales , Sydney , New South Wales 2052 , Australia
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47
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Haas B, Rouvière JL, Boureau V, Berthier R, Cooper D. Direct comparison of off-axis holography and differential phase contrast for the mapping of electric fields in semiconductors by transmission electron microscopy. Ultramicroscopy 2019; 198:58-72. [DOI: 10.1016/j.ultramic.2018.12.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 11/30/2018] [Accepted: 12/05/2018] [Indexed: 11/24/2022]
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48
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Seki T, Ikuhara Y, Shibata N. Theoretical framework of statistical noise in scanning transmission electron microscopy. Ultramicroscopy 2018; 193:118-125. [DOI: 10.1016/j.ultramic.2018.06.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 06/15/2018] [Accepted: 06/17/2018] [Indexed: 01/30/2023]
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49
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Hachtel JA, Idrobo JC, Chi M. Sub-Ångstrom electric field measurements on a universal detector in a scanning transmission electron microscope. ADVANCED STRUCTURAL AND CHEMICAL IMAGING 2018; 4:10. [PMID: 30221126 PMCID: PMC6132373 DOI: 10.1186/s40679-018-0059-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 08/09/2018] [Indexed: 11/25/2022]
Abstract
Scanning transmission electron microscopy (STEM) excels in accessing atomic-scale structure and chemistry. Enhancing our ability to directly image the functionalities of local features in materials has become one of the most important topics in the future development of STEM. Recently, differential phase contrast (DPC) imaging has been utilized to map the internal electric and magnetic fields in materials from nanoscale features such as p-n junctions, skyrmions, and even from individual atoms. Here, we use an ultra-low noise SCMOS detector in as the diffraction plane camera to collect four-dimensional (4D) datasets. The high angular resolution, efficient high-SNR acquisition, and modifiability of the camera allow it to function as a universal detector, where STEM imaging configurations, such as DPC, bright field, annular bright field, and annular dark field can all be reconstructed from a single 4D dataset. By examining a distorted perovskite, DyScO3, which possesses projected lattice spacings as small as 0.83 Å, we demonstrate DPC spatial resolution almost reaching the information limit of a 100 keV electron beam. In addition, the perovskite has ordered O-coordinations with alternating octahedral tilts, which can be quantitatively measured with single degree accuracy by taking advantage of DPC's sensitivity to light atoms. The results, acquired on a standard Ronchigram camera as opposed to a specialized DPC detector, open up new opportunities to understand and design functional materials and devices that involve lattice and charge coupling at nano- and atomic-scales.
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Affiliation(s)
- Jordan A. Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Miaofang Chi
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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50
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Prozorov T, Almeida TP, Kovács A, Dunin-Borkowski RE. Off-axis electron holography of bacterial cells and magnetic nanoparticles in liquid. J R Soc Interface 2018; 14:rsif.2017.0464. [PMID: 29021160 DOI: 10.1098/rsif.2017.0464] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/18/2017] [Indexed: 12/19/2022] Open
Abstract
The mapping of electrostatic potentials and magnetic fields in liquids using electron holography has been considered to be unrealistic. Here, we show that hydrated cells of Magnetospirillum magneticum strain AMB-1 and assemblies of magnetic nanoparticles can be studied using off-axis electron holography in a fluid cell specimen holder within the transmission electron microscope. Considering that the holographic object and reference wave both pass through liquid, the recorded electron holograms show sufficient interference fringe contrast to permit reconstruction of the phase shift of the electron wave and mapping of the magnetic induction from bacterial magnetite nanocrystals. We assess the challenges of performing in situ magnetization reversal experiments using a fluid cell specimen holder, discuss approaches for improving spatial resolution and specimen stability, and outline future perspectives for studying scientific phenomena, ranging from interparticle interactions in liquids and electrical double layers at solid-liquid interfaces to biomineralization and the mapping of electrostatic potentials associated with protein aggregation and folding.
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Affiliation(s)
- Tanya Prozorov
- Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
| | - Trevor P Almeida
- Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - András Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
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