The transmission electron microscope (TEM) is one of the most powerful imaging instruments. It works similarly to an optical microscope, but instead of using visible light, a TEM generates an accelerated electron beam that passes through a thin sample. The transmitted beam then interacts with a set of lenses that magnifies the sample image onto a camera detector. Because of diffraction limits, an optical microscope’s resolution can be no better than one-half the wavelength of light, or about 200 nm. But accelerated electrons in a TEM have much shorter wavelengths, making it possible to see 3D, atomic-scale features.
After the invention of the TEM in the early 1930s, for which some of its inventors were awarded the 1986 Nobel Prize in Physics, its imaging capabilities have been expanded significantly. In the TEM family of techniques, electron diffraction can be used to image crystallographic structure at subatomic resolution. Electron energy-loss spectroscopy...
