Nanometer-resolution surface analysis with Auger electrons

High spatial resolution Auger electron spectra and images have been obtained in a UHV scanning transmission electron microscope. An edge resolution of ≈ 1 nm has been achieved in Auger electron images of thin specimens. The attenuation lengths of the collected Auger electrons and the escape depth of the high energy background secondary electrons have been estimated from these nanometer-resolution images. Surface steps are clearly visible in Auger electron images with high contrast and high resolution. These techniques have been applied to study a model catalyst system. A method has been developed to estimate the number of atoms in metal particles which are smaller than the probe size. The most recent results show that Ag clusters containing less than 10 atoms can be readily detected when supported on thin substrates.