Kinetics of surface and interface segregation in stressed nano-films on inert substrate

A general model is developed for describing the kinetic segregation in stressed ultrathin alloy films deposited on inert substrates. The essential role of the diffusion-induced stress and the intrinsic stress in ultrathin films upon the kinetic surface and interface segregation is addressed. By the developed model, it is demonstrated that the equilibrium segregation is the natural consequence of the kinetic segregation. The influences of temperature, film thickness, and average concentration on the surface and interface segregation are evaluated. As an example, the model is applied to simulate the kinetic surface/interface segregation in ultrathin Ni(111)(Au) alloy films deposited on the sapphire substrate and the simulation results are in agreement with the experimental observations.