Mechanisms of complex morphological evolution during solid-state dewetting of single-crystal nickel thin films

We report studies of complex morphological evolution during solid-state dewetting of 120 nm thick single-crystal Ni(100) and Ni(110) thin films on MgO(100) and MgO(110) substrates. During dewetting, holes that form in the Ni films evolve to complex shapes that depend on the crystallographic orientation of the films and annealing ambient. We characterize the origins of hole, line, and particle morphologies that develop during the dewetting process, and identify a sequence of instabilities that control the morphological evolution. This study provides mechanistic insights for control of dewetting to produce specific ordered structures.