Transmission electron microscopy (TEM) is a microscopic method that may provide images with a resolution of just a few angstroms (approximately 0.19nm). It scans thin samples by detecting a series of secondary signals generated by electrons passing through the sample, allowing researchers to analyze the nano-scale shape and chemical properties of materials down to the atomic level. Brightfield imaging, darkfield imaging, electron diffraction, energy-dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), scanning transmission electron spectroscopy (STEM), and nano-tomography are just a few of the applications (3D analysis).
Electrons are emitted from the electron source on top of the TEM and pass through the vacuum in the microscope column. Electrons are focused into a very thin beam and then guided through the material using magnetic lenses. After passing through the sample, the electrons hit the detector. The scattering and disappearance of incident electrons from the beam in traditional brightfield imaging are dependent on the sample's component density and crystal orientation. The unscattered electrons' intensity creates a "shadow image" of the sample, with different portions of the sample appearing in different shades of darkness depending on the density. You may also create a 3D representation of the sample by rotating it and taking numerous photographs with each turn.
Electron diffraction can also be used to examine the crystal structure of a material having a regular atomic structure. Positive interference in the rear focal plane produces discrete locations that can be found electrically and observed by mapping the back focal plane to the imaging equipment. Finally, the diffraction pattern can be utilized to examine the sample's crystal structure.
The EDS in the TEM may detect X-ray emission caused by the interaction of the primary electron beam with the sample. The generated spectrum can be utilized to identify the constituent elements since the generated X-ray energy is typical of the atomic structure of the element from which they originate.
The energy loss of inelastic electron scattering during sample transmission can also be measured using TEM. This data can be utilized to deduce element composition, chemical bonding, valence state, and electronic characteristics of the conduction band.
Hitachi HD2700C Spherical Aberration Corrected Scanning Transmission Electron Microscope (STEM)
The probe forming lens has an aberration corrector, and the equipment is a 200kV cold field emission STEM with secondary electron (SE) imaging capability. The aberration corrector increases the probe current to 200 pA while improving the spatial resolution to less than 0.1 nm. The equipment is designed to do spectral imaging, "Z-contrast" pictures, and electron energy loss spectroscopy all at the same time (EELS). It has five detectors for annular dark-field imaging in diverse circumstances with varied convergence and collection angles. It also has a high-resolution electron energy loss spectrometer, which can attain an energy resolution of 0.35 eV under zero energy loss in most cases. To decrease noise, the instrument is enclosed in a metal box. The SDD EDX detector was fitted to undertake atomic-resolution STEM-EDX investigation of heavy elements.
Thermo Scientific Themis 300 G3 Transmission Electron Microscope
A transmission electron microscope with a field emission gun is a 300kV high-resolution microscope. Energy dispersive spectroscopy, crystal structure determination, diffraction, and crystallographic research are all common uses for the apparatus, which has good analytical performance.
Its atomic-resolution structural imaging is enabled by its high-brightness and high-stability FEG. We can do the most sensitive analysis of the sample with sub-nanometer resolution thanks to the high-brightness sub-nanometer size probe. It has four EDS detectors for quick and accurate spectrum capture.
Metal deformation, nanotechnology, thin films, chemical composition and quantification, element mapping, tomography, and other applications are among them.
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