Nanostructures on GaAs surfaces due to 60Â keV Ar+-ion beam sputtering

► Effect of angle of ion incidence and ion fluence on the surface nanostructures formed due to 60 keV Ar+-ion beam sputtering of p-type GaAs(1 0 0) is examined using an ion current density of 10-12 μA/cm2. ► As a function of angle of incidence the surface topography changes from 'dots + holes' (0°) → 'smooth' (30°) → 'dots' (60°). For 60° off-normal ion incidences ripple formation is suppressed. ► Effectiveness and limitations of existing theories of ion induced pattern formation to explain the observed nanostructures are discussed.