36 results about "Electron diffraction" patented technology

The invention provides a wide bandgap semiconductor heteroepitaxial layer growth process parameter adjustment method and system, and relates to the technical field of semiconductors, and the method comprises the steps: obtaining substrate parameters, constructing a digital twin model, predicting an initial strain evolution trend, and determining an optimal initial process parameter; acquiring multi-source data through an in-situ ellipsometer, a reflective high-energy electron diffraction sensor and an acoustic emission sensor in the growth process, and calculating a strain tensor field and defect density distribution by adopting a deep neural network; layered progressive process parameter optimization is executed; and adjusting the growth process according to an optimization result. According to the method, accurate regulation and control of process parameters can be realized, the defect density is reduced, and the quality of the wide bandgap semiconductor heteroepitaxial layer is improved.

This invention discloses a method for identifying the origin of quartz based on multimodal signal fusion using scanning electron microscopy (SEM). It utilizes only one SEM equipped with an energy dispersive spectroscopy (EDS) probe, a cathodoluminescence (CAT) probe, and a backscattered electron diffraction (BSE) probe. By comprehensively employing multiple indicators, including the coefficient of variation of CL band width (a), the Al-Ti influence coefficient (b), the lattice orientation difference influence coefficient (c), and the relative gravity coefficient of inclusion type (d), the method determines whether a quartz sample is of hydrothermal or metamorphic origin. This invention achieves rapid and accurate identification of the origin of quartz.

The utility model provides a kind of high pressure electron diffraction screen and deposition equipment for RHEED, belong to semiconductor production equipment technical field, including window subassembly, camera subassembly, support subassembly, fluorescence screen, fluorescence screen is set in the side of support subassembly away from window subassembly, can shorten the distance between fluorescence screen and sample, effectively improve measurement accuracy, to solve the deficiency of traditional structure. Wherein window subassembly can be defined on vacuum window in coating cavity, so that there is no obstruction between camera subassembly and fluorescence screen, while not affecting the sealing of coating cavity.

A positive electrode includes a positive electrode active material that includes a lithium nickel-based composite oxide and is in a form of a single particle. A ratio of a volume cumulative average particle diameter (D50) of the positive electrode active material measured using a particle size analyzer to a grain size of the positive electrode active material measured using backscatter electron diffraction after ion milling of the positive electrode is about 1.6 to about 1.8.

The invention discloses an intermediate, a COF material as well as a preparation method and application of the COF material, and a series of imine-connected 3D COFs can be easily synthesized by adopting an intermediate (CIM) with a specific structure and utilizing a conversion scheme of the intermediate. Molecules and crystal structures of crystal intermediates are directly analyzed through three-dimensional electron diffraction (3DED), and the method is an emerging method for analyzing the light beam sensitive nanocrystals. A way from CIM synthesis of 3D COFs crystals to crystal conversion is adopted, and formation of an initial amorphous polymer is avoided. Compared with a classical sealed tube scheme, the novel CIM conversion scheme has several obvious advantages, such as no need of deoxidation operation, lower reaction temperature, higher crystallization efficiency and easier amplification. In addition, the new scheme is further successfully expanded to synthesis of other diamond (dia) net 3D COFs, and wide applicability is proved.

The present disclosure relates to methods of obtaining electron diffraction data of microcrystalline samples.

The invention discloses a film layer monitoring device and epitaxy equipment, the film layer monitoring device is used for vapor phase epitaxy equipment, and the film layer monitoring device comprises an electron beam emission mechanism which comprises an electron emission assembly and an electron channel; the electron emitting assembly is used for generating electron beams; an inlet of the electron channel is communicated with an emitting end of the electron emitting assembly, and an outlet of the electron channel is arranged at a position close to the edge of the wafer; electron beams generated by the electron emitting assembly are glanced to the surface of the wafer through the electron channel so as to be diffracted on the surface of the wafer to form diffracted electron beams; a receiving end of the electron beam receiving mechanism is located in the epitaxial chamber; the electron beam receiving mechanism is configured to capture diffracted electron beams and convert the diffracted electron beams into quantizable signals; the electron beam receiving mechanism is further configured to perform in-situ monitoring on the wafer film layer based on the quantizable signal. The crystal quality and the deposition thickness of the film layer can be monitored in situ in the film growth process, and high-quality imaging of electron diffraction signals can be ensured.

The application provides a preparation method of tellurium nanowires and the tellurium nanowires, and relates to the technical field of semiconductors. The preparation method comprises the following steps: S1, providing a clean substrate; S2, transmitting the substrate in step S1 into a molecular beam epitaxy (MBE) pretreatment chamber to perform a degassing treatment; S3, transmitting the substrate in step S2 into an MBE growth chamber to perform a deoxidation treatment; S4, reducing the substrate in step S3 to a growth temperature; S5, adjusting a tellurium source beam current to a growth value, and growing the tellurium nanowires on the substrate in step S4; wherein, steps S3-S5 are completed under the monitoring of high-energy electron diffraction; the substrate in steps S3-S5 is in a rotating state; and steps S1-S5 are performed in a vacuum environment. The preparation method provided by the application can realize the preparation of large-area high-purity and uniformly-shaped tellurium nanowire arrays.

The application relates to the field of crystal structure symmetry classification and retrieval, and specifically discloses a crystal structure symmetry determination and retrieval method using electron diffraction, which comprises the following steps: a multi-view selected area electron diffraction data input module is used to acquire a two-zone axial diffraction spectrum and perform pretreatment; a symmetry feature coding module is used to extract a single-view descriptor through a double-branch convolutional neural network, to obtain a material descriptor through view pooling fusion; a hierarchical symmetry classification module is used to realize hierarchical classification of crystal systems and space groups, and to guarantee the logic of the results through consistency constraints; a high-dimensional feature embedding and database construction module is used to standardize crystal structure files, to generate descriptors, and to construct a vector database; and a constrained structure retrieval module is used to combine the classification results and user constraints to filter candidate structures, and to complete retrieval through cosine similarity. The application solves the problems of poor generalization, insufficient multi-view feature fusion and inability to associate a crystal library in the prior art, and realizes full-process automation of crystal structure symmetry classification and retrieval.

The application provides a spatial orientation high-resolution mapping method and system for single crystal EBSD, comprising the following steps: S1: collecting diffraction signals of a single crystal sample by a backscattering electron diffraction technology to obtain Euler angle parameters and corresponding spatial coordinates of pixel points; S2: converting the obtained Euler angle parameters into polar angle parameters according to a crystallographic coordinate transformation relationship, and establishing a corresponding relationship between the polar angle parameters and the spatial coordinates; S3: discretizing continuous polar angle information into polar angle grid units; S4: mapping the polar angle parameters of each pixel point to the polar angle grid units to realize attribution determination and partition aggregation of the pixel points in an angle space; and S5: explicitly representing spatial distributions corresponding to each angle unit to establish a mapping relationship between the polar angle and the spatial coordinates.

The application discloses a high-speed quantitative measurement method for microgram-level material gas adsorption and desorption process, and realizes in-situ measurement of gas layer thickness change in a sealed microcavity in a transmission electron microscope on the basis of a sample position measurement method based on micro-area electron diffraction Thon ring, realizes in-situ high-speed measurement of gas capacity released or absorbed by a sample by establishing a relationship curve between the gas layer thickness and the microcavity gas pressure, and achieves high-speed and quantitative measurement of the microgram-level or nanogram-level material gas adsorption and desorption process in a millisecond or even faster scale. The difficulty of directly measuring the gas pressure in-situ in the gas microcavity is solved for the first time, and the method has important significance for studying the gas charging and discharging process of trace materials by means of the electron microscope sealed microcavity in-situ technology. In addition, the method has very high sensitivity and can realize high-precision measurement of sub-nanometer-level gas layer thickness change (<10 ‑9 m) and millibar-level gas pressure change (<10 ‑1 Pa) in the electron microscope microcavity.

To provide a charged particle focusing device using a cylindrically symmetrical rotational crystal capable of realizing the function of an electron diffraction lens.SOLUTION: An electron beam focusing device comprises a rotational crystal film having a cylindrically symmetrical rotational crystal with a thin, planar structure that has been cut out along a vertical plane direction with respect to a polar direction (Z) from a center (O) of a spherical crystal, and that has the thickness between 5 nm and 1 mm. When an incident electron beam passes through the rotational crystal film, the resulting strong scattering points converge at a focal position f located away from the film thickness of the rotational crystal film. Preferably, a polar angle (θ) of the rotational crystal film and a predetermined distance (r) approximately satisfy the following formula with respect to an incident direction (Zbeam) of the incident electron beam and an out-of-plane normal direction [hkl] of the rotational crystal film: r / f=tanθ (where f is a constant).SELECTED DRAWING: Figure 22C

An object of the present invention is to provide a highly crystalline heteroelement-containing graphene. A heteroelement-containing graphene disclosed herein includes carbon (C) and, as a heteroelement (X), at least one element selected from the group consisting of nitrogen (N), phosphorus (P), arsenic (As), sulfur (S), boron (B), and silicon (Si). Also, spots belonging to either the orthorhombic system or the hexagonal system and having the symmetry of a single crystal are observed in the selected area electron diffraction.

The application discloses a kind of high-efficiency accurate simulation three-dimensional electron diffraction dynamics intensity method, to solve the problem of low efficiency in prior art simulation calculation, insufficient accuracy.The method is by optimizing the strategy of inverse space sampling, using Rodrigues formula to rotate inverse vector, and introducing self-defined phase difference or random sampling in rotation and spin two dimensions, significantly reduce the sampling number.At the same time, the diffraction intensity is accurately calculated by using Bloch wave method, and the diffraction intensity of chiral crystal and its enantiomer is calculated by setting negative thickness once, which avoids repeated calculation.The application supports a variety of diffraction methods, including electron diffraction automatic tomography (ADT), rotating electron diffraction (RED), spin electron diffraction tomography (PEDT), continuous rotation electron diffraction (cRED) and continuous rotation spin electron diffraction tomography (cPEDT), and can reach convergence within 50, 100, 500 times sampling of a single diffraction.The method not only improves the calculation efficiency, but also widens the scope of simulation, and provides reliable technical support for material structure analysis.

The invention provides a substance detection system and method and diagnostic equipment, and belongs to the technical field of electron diffraction, and the substance detection system comprises an electron emission module, a laser emission module and a detection module. The electron emission module comprises an electron emitter and a grid electrode. The electron emission module is used for emitting electronic pulses to the to-be-detected sample in the excited state. The grid electrode is arranged on the periphery of the electron emitter and regulates and controls electron beams emitted by the electron emitter. The laser emission module is used for emitting laser pulses to a to-be-detected sample, so that the to-be-detected sample reaches an excited state. And the detection module is used for detecting detection signals obtained by the laser emission module and the electron emission module acting on the to-be-detected sample. The electronic emission module, the laser emission module and the detection module are arranged to be in mutual time synchronization. According to the substance detection system and method provided by the invention, the dynamic process of different substances in different time scales can be represented, and the technical problem that the application range of a traditional system is narrow is solved.

Provided is a technique capable of further assisting measurement in electron diffraction. According to one aspect of the invention, an electron diffraction-based structural analysis device is provided. The configuration analysis device is provided with at least one processor capable of executing a program to perform the following steps. In the display step, an image including the plurality of samples is displayed on the basis of transmitted electron data, which is data of transmitted electrons obtained by irradiating a region including the plurality of samples with an electron beam. In the calculation step, the transmissivity of each of the plurality of samples is calculated on the basis of the transmission electron data. In the selection step, at least one sample satisfying a predetermined condition is selected from the image, and the predetermined condition is a condition related to transmittance.

The utility model discloses a backscattered electron diffraction analysis sample fixing device which comprises a main mounting assembly, an auxiliary mounting inclined plane is arranged on the main mounting assembly, a sample limiting assembly is arranged on the auxiliary mounting inclined plane, a first auxiliary plate is arranged on the inner side of the sample limiting assembly, and a second auxiliary plate is arranged on the outer side of the sample limiting assembly. A plurality of first sample pressing sheets are arranged on the first auxiliary plate, a second auxiliary plate is arranged on the outer side of the main mounting assembly, and a plurality of second sample fixing plates are arranged on the second auxiliary plate. The sample fixing device has the advantages that the sample fixing device is ingenious in structural design, high in practicability and convenient to operate, when the sample fixing device is used, a sample can be rapidly fixed to an electron microscope table, it is avoided that substances such as conductive adhesive and elargol are used for fixing the sample, the sample fixing stability is high, and by means of the sample fixing device, the sample fixing effect is good. The stability of sample clamping is effectively improved, and the accuracy of sample analysis and test results is also effectively improved.

The present invention discloses a method for epitaxially growing chromium telluride thin films exhibiting a significant topological Hall effect. This method, which belongs to the field of electronic materials technology, first prepares a substrate and a chromium-telluride compound target. After the chamber pressure is evacuated to a vacuum using a pump assembly, the substrate is heated to a constant temperature. An excimer laser is focused onto the target. The entire deposition process is monitored in real time using a RHEED high-energy electron diffractometer. After observing that the RHEED diffraction spots of the deposited film form a clear three-dimensional lattice pattern, the chamber temperature is lowered to room temperature, the substrate is removed, and the resulting chromium telluride single crystal thin film is characterized and tested. Measurement results demonstrate that this method is the first in this field to produce a chromium telluride ferromagnetic film with a Curie temperature above room temperature. The maximum amplitude of its topological Hall resistivity is the highest among all chromium telluride material systems in which the topological Hall effect has been observed. The method exhibits high production efficiency and can be expanded to produce other high-quality telluride thin films.

A tool and method for screening cryogenic electron microscopy (cryo-EM) sample grids using vacuum ultraviolet (VUV) illumination in two configurations. First configuration directly images cryo-EM grids using bright-field optical microscopy employing VUV wavelengths and specialized VUV optics. Second configuration converts transmitted VUV radiation from the cryo-EM grid to visible or near-UV light with a scintillator positioned by the grid. The resultant luminescent high-resolution shadow image is viewed using more conventional microscope optics. In both configurations, individual micron-scale grid holes are imaged to determine ice thickness and quality from the optical absorption of ultrathin vitrified water layers with a precision of a few nanometers. Longer wavelengths can be used to independently view protein concentration and distribution within the ice layer. This tool greatly increases yield of high-quality grids before cryo-EM analysis and is compatible with Single Particle Analysis (SPA) and other cryo-EM methods including cryo-electron Tomography and microcrystal electron diffraction.

The invention provides a spatial orientation high-resolution mapping method and system for single crystal EBSD, and the method comprises the steps: S1, collecting a diffraction signal of a single crystal sample through a backscattered electron diffraction technology, and obtaining an Euler angle parameter of a pixel point and a corresponding spatial coordinate; s2, converting the obtained Euler angle parameter into a polar angle parameter according to a crystallographic coordinate conversion relation, and establishing a corresponding relation between the polar angle parameter and a space coordinate; s3, discretizing the continuous polar angle information into polar angle grid units; s4, mapping the polar angle parameter of each pixel point to a polar angle grid unit so as to realize affiliation judgment and partition aggregation of the pixel points in an angle space; and S5, the spatial distribution corresponding to each angle unit is explicitly expressed, so that the mapping relation between the polar angle and the spatial coordinates is established.

The invention belongs to the field of metal material sample preparation, and particularly relates to an oxide scale powder transmission electron microscope sample preparation method which comprises the following steps: 1) grinding oxide scale stripped from the surface of a sample into a nano-scale powder sample; (2) preparing a mixed solvent from absolute ethyl alcohol and deionized water, pouring the oxide scale powder into the mixed solvent, and uniformly stirring; (3) dropwise adding a surfactant into the mixed solvent, uniformly stirring, putting into an ultrasonic cleaner, and carrying out ultrasonic oscillation; (4) flatly placing a piece of carbon support film carrying net for the transmission electron microscope on filter paper with the front face facing upwards, dripping the mixed solvent onto the carbon support film, and naturally drying in the air; and in a high-vacuum coating instrument, vacuumizing, evaporating a carbon film, and releasing vacuum to finish sample preparation. The method has the advantages that the prepared sample is in a thin-layer, uniform and single-particle dispersed state, and the requirements of high-resolution transmission electron microscope (HRTEM) imaging and selective area electron diffraction (SAED) analysis are completely met.

This invention relates to a method for preparing a positive electrode active material, a positive electrode, and a rechargeable lithium battery. The positive electrode includes a positive electrode active material, which comprises a lithium-nickel-based composite oxide and is in the form of single particles. The volumetric cumulative average particle size (D) of the positive electrode active material is measured using a particle size analyzer. 50 The ratio of the grain size of the positive electrode active material measured by backscattered electron diffraction after ion milling of the positive electrode was 1.6 to 1.8.

The present invention relates to a method for growing an indium arsenide quantum dot single-photon source using molecular beam epitaxy, comprising the following steps: (1) growing indium arsenide quantum dots on a substrate using molecular beam epitaxy in a stationary growth manner, and adjusting the indium beam current size to a rate suitable for the growth of the indium arsenide quantum dots; (2) adjusting the growth time of the indium arsenide quantum dots based on the growth time of the indium arsenide quantum dots formed by observing a reflection high-energy electron diffractometer, so that the single-photon source region of the sample is located at the center of the entire sample during stationary growth; and (3) fixing the growth time of the indium arsenide quantum dots, changing the growth mode to a combination of rotational growth and stationary growth, and adjusting the time distribution of the rotational growth and stationary growth during the growth process to achieve regulation of the distribution of the single-photon source region. The present invention achieves regulation of the distribution of the indium arsenide quantum dot single-photon source region, greatly increasing the effective area of ​​the quantum dot single-photon source on the sample, and improving the wafer yield and utilization rate.

The present invention discloses a near-normal-pressure growth method for TMDC materials and an MBE device for near-normal-pressure growth of TMDC materials. The near-normal-pressure growth of TMDC materials in the MBE device comprises the following steps: S1: introducing ambient gas to achieve an adjustable gas atmosphere at near-normal pressure within the cavity; S2: using a fiber-coupled laser heater to heat the target substrate to the target material growth temperature; S3: opening the baffle of the dual-temperature-zone thermal evaporation source, then turning on the excimer laser, and using a 248nm KrF excimer pulse laser to bombard a transition metal element target material to achieve near-normal-pressure growth of the TMDC material, and using a two-stage differential reflection high-energy electron diffractometer for real-time monitoring. The present invention provides a new approach to preparing TMDC materials, improves the main structure of the MBE device, and adds two new dimensions of thin film growth control: pressure and atmosphere, thereby achieving near-normal-pressure growth of TMDC materials.

The invention discloses an arc ablation copper-tungsten contact material performance evaluation method, and belongs to the field of high-voltage switch equipment material testing. The method comprises the following steps: carrying out an ablation test on a material through a high-power pulse discharge system, and measuring a melting threshold value; mass loss before and after ablation is measured, and the ablation rate is calculated; a white light interferometer is used for collecting the three-dimensional shape of an ablation area, and the average melting depth is calculated; counting the maximum crack width of the surface by using a scanning electron microscope, and obtaining the maximum depth of the crack by observing the cross section; analyzing a microstructure by using back scattering electron diffraction, and counting a large-angle grain boundary proportion; and finally, selecting the six parameters as key indexes, and calculating a comprehensive performance score in combination with weight distribution. According to the method, a multi-dimensional evaluation system covering macroscopic thermal damage, surface topography characteristics and a microstructure is constructed, the limitation of single index evaluation is overcome, and accurate quantitative evaluation of arc ablation resistance and crack resistance of the copper-tungsten contact material is realized.

This invention relates to the field of thin film material preparation technology, specifically to a method for preparing a single-crystal transition metal nitride epitaxial thin film with an anti-perovskite structure. In a molecular beam epitaxy (MBE) apparatus, after heating the single-crystal substrate, a transition metal atom beam and an active nitrogen atom beam generated by a radio frequency plasma source are supplied simultaneously and independently. By precisely controlling the beam ratio, growth is kept within a narrow stoichiometric window. During growth, in-situ real-time monitoring is performed using reflective high-energy electron diffraction to ensure the film grows in a two-dimensional layered manner. Finally, the film is slowly cooled in an active nitrogen atmosphere. This method can prepare single-crystal thin films with atomically flat surfaces, high phase purity, excellent crystallinity, and a clear epitaxial relationship, exhibiting fewer nitrogen vacancy defects and significantly optimized magnetic and other physical properties.

The invention provides a preparation method of a wafer-level crystal orientation controllable tellurium film and the tellurium film, and relates to the technical field of semiconductors. The preparation method comprises the following steps: S1, providing a clean single crystal substrate; s2, transferring the substrate into a molecular beam epitaxy pretreatment chamber for degassing treatment; s3, transferring the degassed substrate into a molecular beam epitaxial growth chamber for deoxidation treatment; s4, cooling the deoxidized substrate to a growth temperature; s5, adjusting the tellurium source beam to a growth value, and growing a tellurium film on the substrate cooled to the growth temperature; wherein the step S3 and the step S5 are completed under the monitoring of high-energy electron diffraction; the substrate in the step S3 and the step S5 is in a rotating state; the step S1 to the step S5 are carried out in a vacuum environment; wherein the tellurium source beam is a tellurium elementary substance source beam, the growth value of the tellurium elementary substance source beam is 1 * 10 <-8 >-1 * 10 <-6 > Torr, and the growth temperature is 20-300 DEG C. According to the preparation method provided by the invention, preparation of large-area high-purity crystal orientation controllable tellurium discrete thin films and continuous films can be realized.

The invention discloses a quartz cause identification method based on scanning electron microscope multi-mode signal fusion, which only uses a scanning electron microscope equipped with an energy spectrum probe, a cathode luminescence probe and a back scattering electron diffraction probe. A plurality of index factors such as a CL girdle width variation coefficient a, an Al-Ti influence coefficient b, a lattice orientation difference influence coefficient c and an inclusion type relative specific gravity coefficient d are comprehensively adopted to judge that the quartz sample is a hydrothermal cause or a metamorphic cause. According to the invention, rapid and accurate identification of quartz causes is realized.

The present application belongs to the field of condensed matter physics and material science technology, and particularly relates to an ultrathin single-crystal ferroelectric PZT film and a preparation method thereof. The present application adopts a pulsed laser deposition (PLD) method, and uses pulsed laser to bombard a PZT target material to grow a single-crystal ferroelectric PZT film on a single-crystal substrate. The deposition process includes two stages: a single-crystal layer growth stage and a rapid cooling stage. The method is simple and easy to operate, and the growth of the ultrathin ferroelectric single-crystal film is realized by controlling the laser energy, the substrate deposition growth temperature and the oxygen pressure during the PLD growth. In the present application, a high-energy electron diffraction (RHEED) instrument is used to monitor the growth process in real time, so as to ensure the crystal quality and thickness of the film during the growth. The atomic force microscope is used to observe the morphology of the prepared sample, and the atomic-level flatness of the surface is verified. The PZT film grown on the single-crystal substrate still maintains the ferroelectricity even when it is only 2 lattice layers thick, and the ferroelectric polarization reversal can be realized.

The invention belongs to the field of microcrystal structure analysis, and particularly relates to a MicroED data acquisition and image correction system and method based on software linkage, and the system comprises a data acquisition module and a background correction and format conversion module which are communicated with each other. The data acquisition module is used for controlling the transmission electron microscope to shoot a microcrystalline electron diffraction image of a sample to be detected and outputting the diffraction image to the background correction and format conversion module; the background correction and format conversion module is used for carrying out dark background and bright background correction on the diffraction image; the data acquisition module comprises an electron microscope control unit and a camera control unit, and the camera control unit is used for controlling a camera to carry out image acquisition on the electron microscope and outputting a standardized data packet. According to the invention, on the premise of camera bottom layer driving, MicroED data automatic acquisition and data batch background correction of the interface-free camera can be realized.