Atomistic View Onto Solid State Dewetting: The Role of a Strain Gradient

We present a detailed study of solid state dewetting choosing epitaxial bismuth films on silicon as a model system. Exploiting both diffraction and imaging methods, we determine atomistic parameters like unit cell coverage, lattice spacings and gradients thereof through the analysis of x-ray diffraction crystal truncation rods. We use a Johnson-Mehl-Avrami-Kolmogorov model to describe the kinetics of the dewetting process on an atomic scale. The role of a vertical strain gradient, that impedes solid state dewetting, is revealed and a detailed model for the atomic jump diffusion during dewetting is presented.