Formation of nanodots on oblique ion sputtered InP surfaces

Using a field emission gun based scanning electron microscopy, we report the formation of nanodots on the InP surfaces after bombardment by 100 keV Ar+ ions under off-normal ion incidence (30° and 60° with respect to the surface normal) condition in the fluence range of 1 × 1016 to 1 × 1018 ions cm−2. Nanodots start forming after a threshold fluence of about 1 × 1017 ions cm−2. It is also seen that although the average dot diameter increases with fluence the average number of dots decreases with increasing fluence. Formation of such nanostructured features is attributed due to ion-beam sputtering. X-ray photoelectron spectroscopy analysis of the ion sputtered surface clearly shows In enrichment of the sputtered InP surface. The observation of growth of nanodots on the Ar+-ion sputtered InP surface under the present experimental condition matches well with the recent simulation results based on an atomistic model of sputter erosion.