Investigation of symmetry properties of surfaces by means of backscattered electrons

Secondary-electron imaging is presented as a practical method which allows investigation of the nearsurface structure in real time. It is based on the observation that electrons backscattered from surfaces in the keV range show a strong enhancement of intensity along directions defined by atomic rows. The spatial imaging of such electrons reveals the symmetry of near-surface regions in real space. Three-dimensional views of the solid are readily obtained, which makes this method ideally suited for the study of unknown structures and any material system where there is a change of symmetry.