Nanostructuring of solid surfaces by ion-beam erosion

Extensive experimental investigations are presented on the self-organized formation of regular ordered nanodot structures on InP and GaSb surfaces during ion-beam erosion. It is demonstrated that hexagonally arranged dots can be formed by Ar+ sputter erosion either at normal or, alternatively, at oblique ion incidence with simultaneous sample rotation. The size, the geometrical shape, and the local ordering of these dots are determined by ion energy and ion-incidence angle. At elevated temperatures, square-pattern ordering can occur instead of hexagonal ordering. The experimental findings are critically discussed within the context of a stochastic partial differential equation, intentionally proposed to describe this pattern formation. Provided that ion-induced effective surface diffusion is the dominant relaxation process, this theory is proved to predict quantitatively the formation of a dot pattern and the magnitude of its spatial period at a nearly glancing ion-incidence angle of 75 degrees from normal approximately. Nevertheless, the current status of this theory does not allow a complete description of self-organized nanodot formation by ion-beam erosion.