Transmission Electron Diffraction Patterns Research Articles

Martensitic transformation pathways and crystallographic orientation relationships in steel

Martensite is one of the most important structures determining the ability to tailor the performance of steel and several other engineering materials. In previous studies, the face-centered cubic (FCC) to hexagonal close-packed (HCP) (or body-centered cubic (BCC)) martensitic transformation and the FCC to body-centered tetragonal (BCT) (or BCC) martensitic transformation during deformation and quenching were widely investigated; these transformations usually improve the plasticity and strength of steel, respectively. In this work, detailed transmission electron microscopy (TEM) observations and electron diffraction pattern analyses of the BCT and BCC twins are performed along the [110], [131], and [1¯53] zone axes. The transformation of BCT twins into BCC twins along the [131] zone axis is also analyzed through in situ heating during the TEM observations. The high-resolution TEM observations of mutually perpendicular BCT variants are consistent with the atomic arrangement obtained for the quenching pathway during the martensitic transformation. In addition, different orientation relationships between austenite and martensite are explained in terms of the atomic migration occurring during the deformation pathway and the quenching pathway of the martensitic transformation.

Effects of annealing in vacuum on the microstructure of silicon-containing calcium phosphate films deposited on a ZrNb alloy by radio-frequency magnetron sputtering

Coatings were deposited on the surface of a ZrNb alloy by radio-frequency magnetron sputtering using targets consisting of either pure crystalline hydroxyapatite (HA) or silicon-containing HA (Si-HA). The coated ZrNb samples were heated in a vacuum furnace at a pressure of 5 × 10−5 Torr and temperature 700 °C for 2 h. Precursor powders of silicate-substituted HA [Ca10(PO4)6−x(SiO4)x(OH)2−x, x = 0, 0.5, or 1.72] were used to fabricate the targets for sputtering. The aim of this study was to analyze the effect of Si addition to HA on crystallization behavior and structure of the resulting films using transmission electron microscopy and electron diffraction patterns of selected sites. The average thickness of the films was in the range of 175–345 nm. The Si substitution in HA played a major role in the mechanisms of coating formation and crystallization behavior, which influenced the structure and crystallinity of the layers deposited by radio-frequency magnetron sputtering. Moreover, the results indicate that surface-induced crystallization of the deposited thin films is more pronounced than internal crystallization. A possible mechanism underlying the observed decrease in the crystallization rate with the increasing silicate content in the HA-based films is discussed.

MoxWx–1S2 Nanotubes for Advanced Field Emission Application

AbstractTransition metal dichalcogenide (TMDC) nanotubes complement the field of low‐dimensional materials with their quasi‐1D morphology and a wide set of intriguing properties. By introducing different transition metals into the crystal structure, their properties can be tailored for specific purpose and applications. Herein, the characterization and a subsequent preparation of single‐nanotube field emission devices of MoxWx‐1S2 nanotubes prepared via the chemical vapor transport reaction is presented. Energy‐dispersive X‐ray spectroscopy, Raman spectroscopy, and X‐ray diffraction indicate that the molybdenum and tungsten atoms are randomly distributed within the crystal structure and that the material is highly crystalline. High resolution transmission electron microscopy and electron diffraction (ED) patterns further corroborate these findings. A detailed analysis of the ED patterns from an eight‐layer nanotube reveal that the nanotubes grow in the 2H structure, with each shell consists of one bilayer. The work function of the nanotubes is comparable to that of pure MoS2 and lower of pure WS2 NTs, making them ideal candidates for field emission applications. Two devices with different geometrical setup are prepared and tested as field emitters, showing promising results for single nanotube field emission applications.

The Stacking Faulted Nature of the Narrow Gap Semiconductor Sc2Si2Te6

AbstractCrystals of Sc2Si2Te6 have been grown and its crystal, micro‐ and electronic structures were investigated. The layered character of the title compound exhibits stacking faults that impede a full structural characterization by single crystal X‐ray diffraction due to diffuse scattering. Based on high resolution transmission electron micrographs and diffraction patterns, the stacking faulted nature of the real structure of Sc2Si2Te6 has been revealed. Different stacking models were derived from the idealized, faultless structure and the stacking disorder was quantitatively analyzed by Rietveld refinement of powder X‐ray diffraction patterns. An energetic comparison of the stacking models by density functional theory is in line with the experimental observations. Further, the bonding situation was investigated by electronic structure calculations. Sc2Si2Te6 is a narrow gap semiconductor with an indirect band gap of 0.65 eV.

Theoretical Diffraction Pattern Characteristics of Cubic Twin Crystal

Twin crystal is a common lattice arrangement of crystal structure. The commonly used characterization methods for crystal structure include transmission electron diffraction (TED) pattern and electron backscatter diffraction (EBSD) pattern, but there is currently no specific reference standard for twin crystal. In this research, the mathematical relationship between crystal structure and TED and EBSD patterns of twin was calculated. The characteristics of twin electron diffraction spectrum, as well as the calibration of TED and EBSD patterns, were discussed and analyzed towards the examples of face-centered cubic crystal and body-centered cubic crystal. Overall, our results establish a theoretical calculation standard of diffraction spectrum, which provides a reference for further explorations to characterization of twin crystal structures.

Quantum confinement and effective masses dependence in black phosphorus quantum dots and phosphorene

In the present study, quantum confinement effect in phosphorene and black phosphorus quantum dots is extensively studied from experimental and theoretical viewpoints. These quantum structures were prepared with the help of Benzonitrile solvent using Liquid Phase Exfoliation and solvothermal-assisted Liquid Phase Exfoliation, respectively. On one hand, Fourier-transform infrared spectroscopy shows no sign of phosphorus oxidation in both phosphorene and black phosphorus quantum dots solutions. Furthermore, Raman spectroscopy showed a shift in B2gandAg2 phonon modes for phosphorene and black phosphorus quantum dots as compared to bulk black phosphorus. On the other hand, structural characterization via high-resolution transmission electron microscopy imaging and electron diffraction patterns showed a high degree of crystallinity in both quantum structures with no sign of aggregations. Optical properties characterization showed the expected increase in the bandgap value for both quantum structures, which were supported by theoretical calculations using density functional theory and effective mass approximation. Interestingly, we demonstrate that the quantum confinement observed in phosphorene is weakened to the expected extent, relative to that in BPQDs, by the loss of two confinement dimensions. Appropriate models, describing the bandgap and effective mass dependence as a function of the confinement regime, are presented.

(Invited) Study of HfO2-Based High-k Gate Insulators for GaN Power Device

Gallium nitride (GaN) high-electron-mobility transistor and vertical GaN devices with metal-oxide-semiconductor (MOS) structure have been widely investigated to suppress leakage currents for applications associated with high power and high frequency [1-3]. Metal oxide (High-k) with a high dielectric constant (k)-value have been employed instead of SiO2 from the viewpoint of increasing the physical thickness [4, 5]. HfO2-based materials including HfO2, HfSiOx and HfAlOx are the candidate materials because of its relatively large bandgap (~6.5 eV) and a high k value (> 13) [6-9]. These films for transistor applications are typically fabricated using atomic layer deposition (ALD) because ALD is compatible with semiconductor fabrication process and has a big advantage of conformal film fabrication on three-dimensional structure. In this study, we report comparison of characteristics among HfO2, HfSiOx and HfAlOx gate insulators of GaN MOS capacitors.Pt-gated n-GaN MOS capacitors with HfO2, HfSiOx and HfAlOx gate insulators were prepared as follows. A single HfO2 layer, (HfO2)m/(SiO2)n and (HfO2)m/(Al2O3)n nanolaminate layers were deposited on n+-GaN/n-GaN epilayer by plasma-enhanced ALD at 300°C. The m/n ratio was kept at 2/1. Next, PDA was carried out at 800°C in N2. HfSiOx and HfAlOx films were formed from (HfO2)m/(SiO2)n and (HfO2)m/(Al2O3)n nanolaminate after PDA, respectively. The thicknesses of these films were ~24 nm. Finally, Pt gate electrode was deposited on gate insulator and Pt/Ti ohmic contact was deposited on the n-GaN substrate.The HfSiOx and HfAlOx films had an amorhous structure while HfO2 film had a polycrystalline structure after PDA at 800°C using transmission electron microscopy and electron diffraction pattern analysis. The HfO2 capacitor exhibited a small breakdown electric field (EBD) value of 2.6 MV/cm, defined at a current density of 1.0 × 101 A/cm2, because leakage currents easily flow along grain boundaries of the polycrystalline structure. On the other hand, the EBD values of the HfSiOx and HfAlOx capacitors increased up to 8.5 MV/cm. From capacitance-voltage measurements, the estimated k values of the HfO2, HfSiOx and HfAlOx films were 17.7, 17.2 and 13.5, respectively, as expected. The flatband voltage hysteresis (620 mV) of the HfO2 capacitor was much larger than those (~10 mV) of the HfSiOx and HfAlOx capacitors, indicating that the number of charge trapping/detrapping sites and frequency responsive defects was significantly decreased in the HfSiOx and HfAlOx capacitors. No frequency dispersion of the HfSiOx and HfAlOx capacitors were observed while the HfO2 capacitor showed a large frequency dispersion. The interface state density (Dit) values at Ec - E = 0.25 eV which estimated using the conductance method of the HfSiOx (~1 × 1011cm-2V-1) and HfAlOx (4.4 × 1011cm-2V-1) capacitors were one magnitude lower than that of the HfO2 capacitor (3.1 × 1012cm-2V-1), indicating that the electrical defects at n-GaN/HfSiOx and n-GaN/HfAlOx interfaces were much less than that of the n-GaN/HfO2 interface.We conclude that the HfSiOx and HfAlOx were the attractive materials as gate insulator because of amorphous structure, higher k, relatively low Dit, and high Ebd.This work was supported by JSPS KAKENHI (Grant No. JP20H02189). A part of this work was also supported by the MEXT “Program for research and development of next-generation semiconductor to realize energy-saving society.” Program Grant Number JPJ005357. The authors wish to thank Dr. A. Ohi, Dr. N. Ikeda, and the members of the nanofabrication group of the National Institute for Materials Science for their support during this study.[1] M. Kodama et al., Appl. Phys. Express 1, 021104 (2008).[2] Z. Yatabe et al., J. Phys. D: Appl. Phys. 49, 393001 (2016).[3] T. Oka et al., Appl. Phys. Express 8, 054101 (2015).[4] T. Hashizume et al., Appl. Phys. Express 11, 124102 (2018).[5] T. Kikuta et al, J. Vac. Sci. Technol. A 35, 01B122 (2017).[6] T. Nabatame et al., Appl. Phys. Express 12, 011009 (2019).[7] E. Maeda et al., Microelectron. Eng. 216, 111036 (2019).[8] R. Ochi et al., AIP Advances 10, 065215 (2020).[9] S. Miyazaki et al., ECS Trans. 92, 11(2019).

Electronic surface reconstruction of TiO2 nanocrystals revealed by resonant inelastic x-ray scattering

The identification of lattice multiphases in TiO2 nanocrystals is studied by high resolution transmission electron microscope and electron diffraction patterns. Based on the spectroscopic analysis using soft x-ray absorption and resonant inelastic soft x-ray scattering, it is believed that the oxygen vacancies at the interface exhibit structural distortion of the TiO68− cluster around the defect site as for the multiphase lattice. We elucidate that the extra 3d electrons nearby induce the inelastic scattering features with the excitation energy dependence owing to different energy relaxation processes, a characteristic of the electron-phonon coupling or the nature of the electron-hole pair at the intermediate state. The manifold dd excitations driven by the strong interaction between Ti-3d and O-2p electrons are noticeably rich, coexisting on both Ti and O sites. This sophisticated experiment can advance the perspective of nanocomposite TiO2 for various interactions of surface Ti3+ in applications of future devices.

New Features in Crystal Orientation and Phase Mapping for Transmission Electron Microscopy

ACOM/TEM is an automated electron diffraction pattern indexing tool that enables the structure, phase and crystallographic orientation of materials to be routinely determined. The software package, which is part of ACOM/TEM, has substantially evolved over the last fifteen years and has pioneered numerous additional functions with the constant objective of improving its capabilities to make the tremendous amount of information contained in the diffraction patterns easily available to the user. Initially devoted to the analysis of local crystallographic texture, and as an alternative to both X-ray pole figure measurement and EBSD accessories for scanning electron microscopes, it has rapidly proven itself effective to distinguish multiple different phases contained within a given sample, including amorphous phases. Different strategies were developed to bypass the inherent limitations of transmission electron diffraction patterns, such as 180° ambiguities or the complexity of patterns produced from overlapping grains. Post processing algorithms have also been developed to improve the angular resolution and to increase the computing rate. The present paper aims to review some of these facilities. On-going works on 3D reconstruction are also introduced.

Microstructure of Milled Polyacrylonitrile-Based Carbon Fiber Analyzed by Micro-Raman Spectroscopy and TEM.

Milled polyacrylonitrile (PAN)-based Carbon Fibers (mPCFs) were prepared from PAN-based carbon fibers by using a ball milling process. The resulting structural changes in the mPCFs were analyzed by correlating the analytical results obtained by X-ray diffraction (XRD) and Raman spectroscopy and verified by transmission electron microscopy (TEM) lattice images and diffraction patterns. The crystallite size La calculated from the XRD measurements decreased as the milling time was increased to 12 h and then decreased as the milling time was further increased to 18 h. The La of both partially-milled Carbon Fiber (pmCF) and milled Carbon Fiber (mCF) calculated from the Raman spectroscopy data continuously increased as the milling time increased. The difference may be because XRD measured the entire sample regardless of pmCF and mCF, while Raman spectroscopy was limited to measuring the surface and differentiated pmCF and mCF. As the ball milling time increased, the fiber surface was firstly broken by the impact energy of the balls, decreasing crystallinity, while the La inside the unbroken fibers increased.

The abTEM code: transmission electron microscopy from first principles.

Simulation of transmission electron microscopy (TEM) images or diffraction patterns is often required to interpret experimental data. Since nuclear cores dominate electron scattering, the scattering potential is typically described using the independent atom model, which completely neglects valence bonding and its effect on the transmitting electrons. As instrumentation has advanced, new measurements have revealed subtle details of the scattering potential that were previously not accessible to experiment. We have created an open-source simulation code designed to meet these demands by integrating the ability to calculate the potential via density functional theory (DFT) with a flexible modular software design. abTEM can simulate most standard imaging modes and incorporates the latest algorithmic developments. The development of new techniques requires a program that is accessible to domain experts without extensive programming experience. abTEM is written purely in Python and designed for easy modification and extension. The effective use of modern open-source libraries makes the performance of abTEM highly competitive with existing optimized codes on both CPUs and GPUs and allows us to leverage an extensive ecosystem of libraries, such as the Atomic Simulation Environment and the DFT code GPAW. abTEM is designed to work in an interactive Python notebook, creating a seamless and reproducible workflow from defining an atomic structure, calculating molecular dynamics (MD) and electrostatic potentials, to the analysis of results, all in a single, easy-to-read document. This article provides ongoing documentation of abTEM development. In this first version, we show use cases for hexagonal boron nitride, where valence bonding can be detected, a 4D-STEM simulation of molybdenum disulfide including ptychographic phase reconstruction, a comparison of MD and frozen phonon modeling for convergent-beam electron diffraction of a 2.6-million-atom silicon system, and a performance comparison of our fastimplementation of thePRISM algorithm for a decahedral 20000-atom gold nanoparticle.

The abTEM code: transmission electron microscopy from first principles

Simulation of transmission electron microscopy (TEM) images or diffraction patterns is often required to interpret experimental data. Since nuclear cores dominate electron scattering, the scattering potential is typically described using the independent atom model, which completely neglects valence bonding and its effect on the transmitting electrons. As instrumentation has advanced, new measurements have revealed subtle details of the scattering potential that were previously not accessible to experiment. We have created an open-source simulation code designed to meet these demands by integrating the ability to calculate the potential via density functional theory (DFT) with a flexible modular software design. abTEM can simulate most standard imaging modes and incorporates the latest algorithmic developments. The development of new techniques requires a program that is accessible to domain experts without extensive programming experience. abTEM is written purely in Python and designed for easy modification and extension. The effective use of modern open-source libraries makes the performance of abTEM highly competitive with existing optimized codes on both CPUs and GPUs and allows us to leverage an extensive ecosystem of libraries, such as the Atomic Simulation Environment and the DFT code GPAW. abTEM is designed to work in an interactive Python notebook, creating a seamless and reproducible workflow from defining an atomic structure, calculating molecular dynamics (MD) and electrostatic potentials, to the analysis of results, all in a single, easy-to-read document. This article provides ongoing documentation of abTEM development. In this first version, we show use cases for hexagonal boron nitride, where valence bonding can be detected, a 4D-STEM simulation of molybdenum disulfide including ptychographic phase reconstruction, a comparison of MD and frozen phonon modeling for convergent-beam electron diffraction of a 2.6-million-atom silicon system, and a performance comparison of our fast implementation of the PRISM algorithm for a decahedral 20000-atom gold nanoparticle.

Ab initio description of bonding for transmission electron microscopy

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.

Quantitative agreement between dynamical rocking curves in ultrafast electron diffraction for x-ray lasers

Electron diffraction through a thin patterned silicon membrane can be used to create complex spatial modulations in electron distributions. By precisely varying parameters such as crystallographic orientation and wafer thickness, the intensity of reflections in the diffraction plane can be controlled and by placing an aperture to block all but one spot, we can form an image with different parts of the patterned membrane, as is done for bright-field imaging in microscopy. The patterned electron beams can then be used to control phase and amplitude of subsequent x-ray emission, enabling novel coherent x-ray methods. The electrons themselves can also be used for femtosecond time resolved diffraction and microscopy. As a first step toward patterned beams, we demonstrate experimentally and through simulation the ability to accurately predict and control diffraction spot intensities. We simulate MeV transmission electron diffraction patterns using the multislice method for various crystallographic orientations of a single crystal Si(001) membrane near beam normal. The resulting intensity maps of the Bragg reflections are compared to experimental results obtained at the Accelerator Structure Test Area Ultrafast Electron Diffraction (ASTA UED) facility at SLAC. Furthermore, the fraction of inelastic and elastic scattering of the initial charge is estimated along with the absorption of the membrane to determine the contrast that would be seen in a patterned version of the Si(001) membrane.

Pycotem: An open source toolbox for online crystal defect characterization from TEM imaging and diffraction.

We present a series of tools working together that facilitate the determination of dislocation Burgers vectors and slip planes, interface plane normals and misorientation between two crystals from a series of Transmission Electron Microscopy (TEM) micrographs and diffraction patterns. To that purpose, we developed graphical user interface programs that allow crystal orientation determination from spot diffraction patterns taken at various tilt angles or from Kikuchi patterns crystal representation from stereographic projection plots and determination of geometrical features from series of conventional images taken at different tilt angles. We present working examples that allow a faster and easier way to analyse data that can especially be retrieved during in situ straining experiments where dislocations and grain boundaries need to be characterized. More generally, these tools target material scientists interested in daily microstructural characterization inTEM.

Variation in intraocular lens calcification under different environmental conditions in eyes with supplementary sulcus-supported lenses

PurposeAnalysis of explanted intraocular lenses (IOLs) from pseudophakic eyes with supplementary sulcus-supported IOLs. MethodsIn this laboratory investigation, ten supplementary and capsular bag IOLs were analyzed. All lenses were received between January 2012 and March 2018. Explants were examined morphologically with histological and electron microscopic techniques and patients’ medical history was evaluated. Additionally, we used a technique new to this field: Transmission Electron Microscopy and electron diffraction pattern analysis was performed to investigate the structure of the opacifying crystals in detail. ResultsEleven lenses were explanted due to IOL opacification from seven polypseudophakic eyes: In three cases the supplementary lens calcified, in three cases the capsular bag IOL (both lenses analyzed) and in one case both IOLs (only the supplementary was received). Additional surgical procedures and comorbidities included pars plana vitrectomy or Descemet stripping endothelial keratoplasty and diabetes mellitus. For each opacified lens, a varying layer of a Calcium phosphate beneath the optic surface was apparent. Crystal characterization revealed its composition to be Hydroxyapatite. Conclusions and ImportanceWe report on a series of secondary calcification in lenses explanted from polypseudophakic eyes. In some cases, calcification occurred in the capsular bag lens, in other cases in the supplementary lens, or in both. The severity of the morphological change could be related to the comorbidities and the presence of surgery subsequent to the lens implantations. Detailed morphology of the opacifying crystals was revealed.

Nanostructural Characterization of Nitrogen-Doped Graphene/ Titanium Dioxide (B)/ Silicon Composite Prepared by Dispersion Method

In this study, nitrogen-doped graphene (NrGO)/ titanium dioxide (B) (TiO2(B))/ silicon composites were synthesized by dispersion method. Weight ratios of NrGO:TiO2(B):Si were varied as 9:1:0, 8:2:0, 7:1:2 and 6:2:2. NrGO was prepared from graphite by the Modified Hummers method, followed by heat treatment under nitrogen atmosphere and N-added by annealing with melamine. TiO2(B) was prepared by hydrothermal method and its phase was confirmed by X-Ray powder diffraction pattern (XRD), transmission electron microscopy (TEM) and electron diffraction pattern. Silicon was synthesized from bamboo leaves by combustion followed by magnesiothermic reduction process. The results from XRD could confirm components of the composites and the unchanged phase of TiO2(B). From scanning electron microscopy (SEM) images of the composites, together with energy dispersive spectroscopy (EDS) data, silicon particles were distributed on the surface of NrGO, and TiO2(B) nanorods which are between 0.5-5 µm in length were distributed on the surface and spaces between layers of NrGO, and NrGO/TiO2 8:2 had the most thoroughly distribution of particles.

Effect of Co Substitution on Crystallization and Magnetic Behavior of Fe85.45-xCoxCu0.55B14 Metallic Glass.

The effects of Co for Fe substitution on magnetic properties, thermal stability and crystal structure of Fe85.45−xCoxCu0.55B14 (x = 0, 2.5, 5, 7.5, 10) melt spun amorphous alloys were investigated. The Cu content was firstly optimized to minimize the energy of amorphous phase formation by the use of a thermodynamic approach. The formation of crystalline α-Fe type phase has been described using differential scanning calorimetry, X-ray diffractometry and transmission electron microscopy. The classical heat treatment process (with heating rate 10 °C/min) in vacuum for wound toroidal cores was optimized in the temperature range from 280 to 430 °C in order to obtain the best magnetic properties (magnetic saturation Bs and coercivity Hc obtained from the B(H) dependencies) at 50 Hz frequency. For optimal heat-treated samples, the complex magnetic permeability in the frequencies 104–108 Hz at room temperature was measured. Finally, magnetic core losses were obtained for 1 T/50 Hz and 1.5 T/50 Hz values for samples annealed at T = 310 °C. An analysis of transmission electron microscope images and electron diffraction patterns confirmed that high magnetic parameters are related to the coexistence of the amorphous and nanocrystalline phases.

Raw-to-repository characterization data conversion for repeatable, replicable, and reproducible measurements

The National Institute for Materials Science, Japan, has been developing a materials data platform linked with a materials data repository system for rapid new material searching using materials informatics. Data conversion from raw data to a human-legible/machine-readable data file is one of the key preparation techniques prior to data analysis, where the converted data file should include metainformation. The tools developed by the authors can convert raw data to a structured data package that consists of mandatory and measurement-characterization metadata, primary and raw parameters, and formatted numerical data (FND). The FND are expressed as a matrix type with robust flexibility. This flexibility is achieved by applying the data analysis architecture of schema-on-read, not schema-on-write based on de jure standards, such as ISO documents. The primary parameters are carefully selected from raw parameters, and their vocabularies are transformed from instrument-dependent terms to general terms that everyone can readily understand. The converted data are linked with, for example, specimen information, process information, specimen handling records, and the electronic laboratory notebook. Using this raw-to-repository (R2R) conversion flow, the authors demonstrated that they can generate and store interoperable data files of x-ray photoelectron spectroscopy (XPS) spectra and depth profiles, powder x-ray diffraction patterns, (scanning) transmission electron microscope images, transmission electron diffraction patterns, electron energy-loss spectroscopy spectra, and calculated electron inelastic mean free path data. Linking measurement data to other required information ensures experimentally repeatable, replicable, and reproducible results. The mandatory and characterization metadata are used for quick electronic searching, and primary and raw parameters are convenient for setting up measurement conditions and useful for reproducibility/replicability and replicability/repeatability, respectively. The FND are human legible and machine readable using parser software, leading to a long lifetime of data utilization. The authors also developed a system to allow the semiautomatic data transfer from an instrument-controlling personal computer (PC) isolated from the communication network by adopting a Wi-Fi-capable secure digital card’s scripting capability while keeping the PC offline. They are developing further software for on-demand data manipulation after R2R data conversion. To date, it has been possible to perform XPS peak separation using an automated information compression technique without any a priori assumption. By combining R2R conversion with a high-throughput data collection system and automated data analysis routine, highly reproducible data acquisition and data analysis could be achieved, where human interaction is minimized. At this early stage, the authors demonstrate automated peak separation processing for XPS C 1s and O 1s narrow spectra of polyethylene terephthalate with very high reproducibility.

Decoding crystallography from high-resolution electron imaging and diffraction datasets with deep learning.

While machine learning has been making enormous strides in many technical areas, it is still massively underused in transmission electron microscopy. To address this, a convolutional neural network model was developed for reliable classification of crystal structures from small numbers of electron images and diffraction patterns with no preferred orientation. Diffraction data containing 571,340 individual crystals divided among seven families, 32 genera, and 230 space groups were used to train the network. Despite the highly imbalanced dataset, the network narrows down the space groups to the top two with over 70% confidence in the worst case and up to 95% in the common cases. As examples, we benchmarked against alloys to two-dimensional materials to cross-validate our deep-learning model against high-resolution transmission electron images and diffraction patterns. We present this result both as a research tool and deep-learning application for diffraction analysis.