Nanostructure evolution during thin film deposition

It is shown how that the combination of atomic deposition and nonlinear diffusion may lead, below a critical temperature, to the growth of nonuniform layers on a substrate. The dynamics of such a system is of the Cahn–Hilliard type, supplemented by reaction terms representing adsorption–desorption processes. The instability of growing uniform layers leads to the formation of nanostructures which correspond to regular spatial variations of substrate coverage. Patterns wavelengths and symmetries are selected by the dynamics and not by variational arguments. For temperatures below critical, one should observe hexagonal arrays of high coverage dots on the surface of otherwise uniform growing layers. On decreasing further the temperature, these structures should transform into hexagonal arrays of low coverage domains, within the growing layer.