Methods of collecting diffractionpatterns from a microcrystal having an ordered array of a molecule are disclosed, which nclude using an exposure rate of at most 0.02 electrons per square angstrom per second on the microcrystal and using a direct electron etector to record electron diffraction patterns. Also disclosed are methods of determining a structural model for a molecule, identifying a material present in a trace amount within a sample, identifying a polymorph, and identifying the stereochemistry of a molecule.

Methods of collecting diffractionpatterns from a microcrystal having an ordered array of a molecule are disclosed, which nclude using an exposure rate of at most 0.02 electrons per square angstrom per second on the microcrystal and using a direct electron etector to record electron diffraction patterns. Also disclosed are methods of determining a structural model for a molecule, identifying a material present in a trace amount within a sample, identifying a polymorph, and identifying the stereochemistry of a molecule.

The present disclosure concerns an electron microscopy method, including the emission of a precessing electron beam and the acquisition, at least partly simultaneous, of an electron diffraction pattern and of intensity values of X rays.

The present disclosure concerns an electron microscopy method, including the emission of a precessing electron beam and the acquisition, at least partly simultaneous, of an electron diffraction pattern and of intensity values of X rays.

The disclosure relates to a method for characterizing a two-dimensional nanomaterial sample. The two-dimensional nanomaterial sample is placed in a vacuum chamber. An electron beam passes through the two-dimensional nanomaterial sample to form a diffraction electron beam and a transmission electron beam to form an image on an imaging device. An angle θ between the diffraction electron beam and the transmission electron is obtained. A lattice period d of the two-dimensional nanomaterial sample is calculated according to a formula d sin θ≅dθ=λ, where λ represents a wavelength of the electron beam.

The disclosure relates to a low energy electron microscopy. The electron microscopy includes a vacuum chamber; an electron gun used to emit electron beam; a diffraction chamber; an imaging device; a sample holder used to fix two-dimensional nanomaterial sample; a vacuum pumping device; and a control computer. The electron beam transmits the sample to form a transmission electron beam and diffraction electron beam. The control computer includes a switching module to switch the work mode between a large beam spot diffraction imaging mode and small beam spot diffraction imaging mode.

An apparatus for detecting Kikuchi diffraction patterns is provided. The apparatus comprises: an electron column adapted in use to provide an electron beam directed towards a sample, the electron beam having an energy in the range 2 keV to 50 keV, and; an imaging detector for receiving and counting electrons from the sample due to interaction of the electron beam with the sample, the detector comprising an array of pixels and having a count rate capability of at least 2,000 electrons per second for each pixel, wherein: the imaging detector is adapted to provide electronic energy filtering of the received electrons in order to count the received electrons which are representative of the said diffraction pattern, and the particle detector has an inert layer on the surface where the electrons enter towards the active region of the detector, wherein the inert layer disperses the detected energy of 20 keV incident electrons with an energy spread having a full-width half maximum less than 3.2 keV. A method for detecting Kikuchi diffraction patterns is also provided.

An apparatus for detecting Kikuchi diffraction patterns is provided. The apparatus comprises: an electron column adapted in use to provide an electron beam directed towards a sample, the electron beam having an energy in the range 2 keV to 50 keV, and; an imaging detector for receiving and counting electrons from the sample due to interaction of the electron beam with the sample, the detector comprising an array of pixels and having a count rate capability of at least 2,000 electrons per second for each pixel, wherein: the imaging detector is adapted to provide electronic energy filtering of the received electrons in order to count the received electrons which are representative of the said diffraction pattern, and the particle detector has an inert layer on the surface where the electrons enter towards the active region of the detector, wherein the inert layer disperses the detected energy of 20 keV incident electrons with an energy spread having a full-width half maximum less than 3.2 keV. A method for detecting Kikuchi diffraction patterns is also provided.

A diffraction pattern is averaged with adjacent diffraction patterns to increase a signal to noise ratio thereof and improve indexing accuracy. The pixels of a diffraction pattern image are averaged with a correlated pixel from one or more adjacent diffraction patterns. Noise artifacts are reduced in intensity, while signals present in each of the patterns reinforce one another to produce an averaged diffraction pattern which is then indexed.

A sample (4) is created by cutting out a device on a plane (10-10). The device has a gate electrode (3) formed along a direction [2-1-10] on a plane c (0001) of a compound semiconductor (1) having a wurtzite structure. Edge dislocations having Burgers vectors of 1/3[2-1-10] and 1/3[−2110] and mixed dislocations having Burgers vectors of 1/3[2-1-13] and 1/3[−2113] are observed by making an electron beam (5) incident on the sample (4) from a direction [−1010] using a transmission electron microscope.