What Is Electron Microscopy?
Most of us are familiar with traditional optical microscopes. We’ve used them since we were in grade school to magnify anything we could fit under a lens and view in epic proportions. Electron microscopy takes this a step further: instead of light, it uses a focused beam of electrons, enabling us to resolve features thousands of times smaller than what optical microscopes can detect, down to the scale of atoms.
There are two primary types of electron microscopy; TEM and SEM. Each has specialized variants like Cryo-EM, STEM, and ESEM.
Because the electron’s wavelength is thousands of times shorter than visible light, electron microscopes achieve resolution many orders of magnitude higher than ordinary optical microscopes. We are then able to observe structural details in the nanometer and even atomic scale that is well beyond the capabilities of light instruments, no matter what the power of their lenses.
Covalent’s Electron Microscopy services allow for either TEM or SEM, as your use case requires.
How It Works
Electron microscopy forms images using electrons in a vacuum to achieve very high resolution. An electron source and magnetic lenses create and focus the beam. The beam interacts with the sample to generate signals that are collected as grayscale images.
- SEM: The beam scans the surface. Detectors capture emitted electrons to show topography, defects, particles, and coatings. Nonconductive samples may be lightly coated to reduce charging.
- TEM: Electrons pass through an ultra thin specimen. Images and patterns reveal internal structure, phases, and interfaces at nanometer to atomic scales.
- Sample prep: Most samples require careful preparation for vacuum and beam conditions. Biological and polymer materials may need dehydration or cryo methods. Materials can be polished or thinned, including FIB when site specific prep is required.
Techniques Used in Electron Microscopy
Atomic Resolution Electron Microscopy (AEM)
Images atoms and maps composition, bonding, and strain. Explore
Focused Ion Beam Scanning Electron Microscopy (FIB-SEM)
Combines ion milling and electron imaging for nanoscale analysis. Explore
Scanning Electron Microscopy (SEM)
Images surface topography and composition with electrons. Explore
Scanning Transmission Electron Microscopy (STEM)
Provides atomic-scale imaging and spectroscopic mapping. Explore
Transmission Electron Microscopy (TEM)
Images atomic structure, defects, interfaces with sub-nm resolution. Explore
