Electron microscopes utilize a beam of accelerated electrons as a source of illumination, as opposed to light microscopy which uses visible light. By using electrons which have wavelengths about 100,000 times shorter than visible light photons, electron microscopes have vastly higher resolving power than light-based versions and can image objects as small as individual atoms. There are two main types of electron microscopes - transmission electron microscopes (TEM) and scanning electron microscopes (SEM).

Transmission Electron Microscope Industry

TEMs use a high-voltage electron beam that is transmitted through an ultra-thin specimen to map the interaction of Global Electron Microscope with the specimen. The resulting image provides information about the specimen's internal structure, crystal orientation, and other characteristics at resolutions around 0.2 nm. TEMs are widely employed in materials science research to study defects, grain structure, and other properties of crystalline samples. Biological applications involve imaging thin sections of cells and tissues, revealing ultrastructures such as organelles, cytoskeleton components, and viruses. Recent advances include aberration-corrected TEMs capable of sub-angstrom resolutions, enabling direct visualization of individual atoms and bonds. Cryo-TEMs use vitrified specimens at liquid nitrogen temperatures to image biological samples in a near-native state.

Scanning Electron Microscopes

SEMs generate images by scanning the specimen surface with a focused electron beam and collecting signals from electron-sample interactions. The signals include secondary electrons that produce very high-resolution images revealing surface topography and morphology down to the 5 nm range. Backscattered electrons provide images of contrasts in atomic number, allowing discrimination between different materials in a sample. Energy-dispersive X-ray spectroscopy (EDS) in SEMs enables elemental analysis and chemical characterization of surfaces. Applications cover diverse fields such as materials science, biology, metallurgy, and geology. Environmental SEMs operate at low vacuum pressures and high resolutions needed for non-coated insulating samples like metals or minerals. Cryo-SEM uses freezing to image moist biological samples.

Electron Microscopy Facilities Globally

Large centralized electron microscopy facilities with state-of-the-art instruments have become essential infrastructure for advanced research. Examples include the National Center for Electron Microscopy (NCEM) at Lawrence Berkeley National Laboratory in the U.S. housing high-performance TEMs and SEMs. The Delft University of Technology in the Netherlands houses the advanced microscopy facility CEOS with multiple aberration-corrected microscopes. MIT's Materials Research Laboratory has provided access to TEMs, microscopes, and tools since opening in the 1970s. In the UK, facilities at University of Cambridge and University of Oxford offer training and access to leading electron microscopes. Several national user facilities operate in countries like Japan, Germany, Taiwan, Brazil and South Korea. Additionally, major microscope manufacturers establish user laboratories near their headquarters to demonstrate instrument capabilities.

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