Abstract Edmund Seebauer Surface diffusion on semiconductors is examined in this study using two experimental approaches and molecular dynamics. The previously developed applications of second harmonic microscopy (SHM) for study of low-coverage surface diffusion in Group IV semiconductors is broadened to include III-V and II-IV materials. This includes the first quantitative measurements of ion-enhanced surface diffusion. The effort focusses on wide bandgap materials which may show very pronounced ionic effects on surface diffusion. In addition, spatially unresolved second harmonic generation is used to test the general theory connecting surface diffusivities with reaction rate constants. Initial experiments involve chlorine on silicon (111). Extension to halogens or hydrogen on III-V or II-VI materials is planned if initial tests succeed. Finally, molecular dynamics simulations of the influence of adatoms on surface heterodiffusion are performed. This is a basic study of the fundamentals of surface diffusion. It has a broad range of potential relevance, including the processing of electronic materials, thin-film formation, heterogeneous catalysis, and corrosion protection. ***