The image of an unstained specimen observed by scanning transmission electron microscopy is a two-dimensional representation of the distribution of the mass of the specimen projected onto a plane, since elastic scattering of the electrons depends on the electron density, which, in turn, is related directly to the mass density of the object being viewed. If the contribution of the sample support is subtracted and comparison is made with an appropriate mass standard, mass or mass density determinations can be derived.
Keywords: STEM; dark-field imaging; electron scattering; sample preparation




