Transmission Electron Microscope - a beam of electrons passes through a thin section of a specimen. Areas that absorb the electrons appear darker on the electron micrograph that is produced.
how do SEM work?
Scanning Electron Microscope - a beam of electrons passes across the surface and scatter. The pattern of scattering builds up a 3D image depending on the contours of the specimen.
problems with using a TEM?
Specimens have to be very thin, particularly for TEM so that the electrons can pass through.
The whole system must be in a vacuum so living specimens cannot be observed.
Artefacts may be produced due to complex staining and prep process.
2D and not in colour
problems with SEM?
SEM has a lower resolving power than TEM, but both have greater resolving power than a light microscope.
