SEM: Imaging with Back-scattered Electrons

Since heavy atoms with a high atomic number Z are stronger scatterers than light ones, images recorded with back-scattered electrons (BSE) contain compositional information.
Examples
SEM images of Fe particles in carbon obtained with secondary electrons (left) and back-scattered electrons (right). The BSE image shows the Fe particles with bright contrast. SEM images of Pt particles on alumina. The SE image (left) shows the morphology only, while the Pt particles appear with bright contrast in the BSE image (right). Sample: Hess, Baiker SEM basics \| SE Imaging

ETH Zürich | ETH chemistry department | ETH inorganic chemistry