In a TEM, which is similar in principle to an inverted light microscope, electrons pass through the sample instead of photons. The TEM allows the imaging of ultrafine structures with a current resolution limit of 0.045 nm (1). The energy of the primary electrons determines the resolving power. Accelerating voltages of 120, 200 and 300kV are common. The electron beam is generated in the upper part between the cathode and the anode followed by the condenser lenses which focus the beam onto the object. The beam then passes through the sample inside the TEM column and reaches the objective lenses. The focal length of the electromagnetic lenses can be varied by changing the current flow. Electron microscopy is always performed under vacuum so that the electrons can "fly" far enough, have a long free path - are not deflected by gas molecules. For imaging, electrons in the imaging plane are captured, which have been scattered by the interaction of the electron beam with the sample. High image quality is closely related to the right preparation method and a low sample thickness, as well as the technical design and condition of the TEM instrument.

Providing Solutions: TEM Imaging Issues and Solutions (PDF)

Guidelines: Qualitative X-ray Analysis (PDF)

Protocol: Developing TEM Imaging Films (PDF)