FIELD-ION MICROSCOPE STUDIES OF SINGLE-ATOM SURFACE-DIFFUSION AND CLUSTER NUCLEATION ON METAL-SURFACES

After nearly 30 years of research, investigations of surface diffusion and cluster nucleation phenomena with the field ion microscope (FIM) continue to provide new insights into the fundamental aspects of atomic interactions on solid surfaces. In this article I review the experimental procedures used in FIM surface diffusion studies and discuss the results in relation to the atomistics of crystal and epitaxial growth processes. Diffusion parameters for over 20 metal-metal combinations are tabulated and chemical trends associated with the measured values are examined. Experiments and theories leading to the discovery of novel diffusion modes and unexpected cluster configurations are described in detail. The influence of surface defects, such as lattice steps and substitutional impurity atoms, as well as external perturbations, such as chemisorbed atoms and applied electric fields, on the surface diffusion rate and transport mechanism is discussed. Methods to extract quantitative information on a variety of atom-surface, atom-defect, and atom-atom interactions are also described. The article is concluded with a section describing the contributions of various theoretical models to the interpretation of FIM experimental results.