Effects of lattice steps in surface diffusion and epitaxial growth

The lattice step is an integral part of a surface. We report a study of the behavior of atoms at and near lattice steps since this behavior plays an important role in epitaxial growth and in affecting the structure of the thin films, particularly grown from the vapor phase, and also the dynamic behavior of the surface at elevated temperature. We use Ir surfaces as our model system, and study self-diffusion on the terrace as well as along the step edges of the (001) and (111) surfaces using the field ion microscope. We also study the descending and ascending motion of diffusion atoms at lattice steps and the upward movement of in-layer atoms to the upper terrace.