Thin film growth of incompatible materials

We study both submonolayer and multilayer growth in a model of thin-film growth appropriate for the case in which the deposited material is “incopatible” with the substrate in the sense that the deposited atoms do not wet the substrate. We find that the scaling behavior of the monomer and island densities, when considered as functions of the first layer coverage θ1 and the ratio D/F of monomer diffusion rate D to the deposition flux F is similar to that for ordinary submonolayer growth. However, the surface morphology is very different. In particular, the substrate remains incompletely covered, with large grooves between the three-dimensional islands up to fairly large coverage. On the other hand, the nonwetting (hopping-up) process and the step barrier yield dimer and trimer mobilities which lead to a three-dimensional island-size-distribution scaling function which is dependent on the values of D/F. For D/F = 107 and low coverage, the scaling function was found to be similar to that for submonolayer growth with critical island size i = 2, while for D/F = 108, it appears to be similar to that for i = 3.