Effects of lattice steps on atom dynamics, surface diffusion and epitaxial growth

When an adatom encounters a lattice step, it can either be reflected or not reflected regardless of whether the step is a 'descending' or an 'ascending' step. These two types of steps are remarkably similar. In addition, lattice steps can act as atom-trap boundaries for diffusing atoms. Our FIM studies are briefly summarized. Based on our experimental data, we explain in simple terms that the 'high temperature' behavior of surface atoms and growth structures in thin film epitaxy are determined by the atom trapping property of the steps, whereas the 'low temperature' behavior and growth structures are determined by the reflection property of the steps.