We present the molecular beam epitaxy (MBE) fabrication of GaAs ring/disk nanostructures. In this system, a central quantum ring is surrounded by a flat outer disk-like region, which is developed following a layer-by-layer growth mode. We studied the influence of the growth temperature on the morphology of these nanostructures and found out a pronounced dependence only for the outer region diameter, which is interpreted in terms of larger Ga atoms surface diffusion length at higher temperatures. Our experimental data provide a fundamental parameter to control the final shape of GaAs coupled ring/disk nanostructures. (C) 2010 Elsevier B.V. All rights reserved.