We demonstrate the formation of hexagonal nanodot arrays with mean dot diameter and periodicity of (73 +/- 10) and 85 nm, respectively, by 1 keV At+ beam sputtering of InP(100) at normal incidence. The ordering of nanodots increases with sputtering duration and ion flux. Ordered hexagonal nanodot arrays form at a small temperature window near room temperature. X-ray photoelectron spectroscopy and backscattered electron composition imaging (COMPO) show that the surface of nanodots comprises primarily of elemental In due to the preferential sputtering of P. Based on scaling theory, the temporal evolution of the sputtered surface can be divided into two different regimes: coarsening in the early-time regime and ordering in the late-time regime. (c) 2006 American Vacuum Society.