IMAGING OF SURFACES BY MEANS OF SECONDARY ELECTRONS

Secondary electrons emitted from crystal surfaces show a strong enhancement of intensity along directions defined by atomic rows. The gross features of such patterns are for-med by the projection of surface layers illuminated by an internal source of electrons. The patterns reveal crystallographic directions and planes at atomic resolution. While the strongly forward-peaked electron-atom scattering is responsible for the observed symmetry, these secondary electron diffraction (SED) patterns also contain features due to Bragg-like diffraction at interatomic planes.