InP/Gd2O3 heterostructures have been prepared by molecular beam epitaxy of Gd2O3 on InP nanowires grown on silicon substrates by molecular beam epitaxy assisted with the vapor-liquid-solid method. Transmission electron microscopy showed Gd2O3 nanocrystals, having diameters between 3 and 7 nm, decorating the sidewalls of InP nanowires. No epitaxial relationship was observed between Gd2O3 nanocrystals and InP nanowires due an amorphous interfacial layer. Depending on the Gd2O3 growth temperature, two morphologies have been highlighted. For Gd2O3 grown at 30 degrees C, anisotropic heterostructures made of oxide nanocrystals covering just one side of the nanowires were observed, while at 250 degrees C Gd2O3/InP core/shell nanowires were identified. (C) 2012 Elsevier B.V. All rights reserved.