The impact of ad-dimer diffusion on the morphology of an epitaxially growing stepped surface was studied analytically and by using kinetic Monte Carlo simulations. It was shown that, if diffusing adatoms were hindered by an Ehrlich-Schwoebel barrier at step edges, ad-dimer diffusion gave rise to a step-bunching instability; provided that the corresponding Ehrlich-Schwoebel barrier for ad-dimers was small or absent.

Dimer Diffusion as a Driving Mechanism of the Step-Bunching Instability during Homoepitaxial Growth. M.Vladimirova, A.De Vita, A.Pimpinelli: Physical Review B, 2001, 64[24], 245420 (6pp)