Speaker
Description
Solid-state dewetting is the process through which thin solid films break and retract on a substrate, leading to the formation of nanostructures. Dewetting in single-crystalline films is well understood as a surface-energy-driven phenomenon governed by surface diffusion. Polycrystalline films, by contrast, exhibit additional complexity due to the presence of extended defects (grain boundaries) forming between crystalline domains with different crystallographic orientations. To date, most theoretical and computational investigations have focused on the single-crystalline case. This presentation illustrates a grand-potential multi-phase-field model for simulating the dewetting of thin polycrystalline films. Assuming isotropic surface and interface energies, we demonstrate agreement with predictions based on energetic considerations and with the expected morphological evolution toward equilibrium. We further derive new analytical criteria for the onset of three-dimensional dewetting, providing fundamental theoretical benchmarks, and elucidate the key role of triple junctions in the dewetting dynamics. Finally, we investigate the dewetting behavior of finite polycrystalline patches, extending the scenarios previously established for single-crystalline films. Future perspectives towards including anisotropic surface and grain-boundary energies, as well as incorporating shear-coupled grain-boundary migration, are discussed.