Au-Cu2O core-shell nanocubes with edge dimensions of 15-45 nm have been produced by annealing a copper grid at 300 degrees C in air in the presence of tetraoctylammonium bromide-stabilized gold nanoparticles. The microstructure of these novel heterostructures, especially the interface between gold nanoparticle core and Cu2O shell, has been investigated in detail using high-resolution transmission electron microscopy (HRTEM). Chemical analyses have been performed on a single Au-Cu2O core-shell nanocube using energy dispersive X-ray spectroscopy (EDS) in the scanning transmission electron microscopy ( STEM). Based on the experimental results, a growth mechanism is proposed. (c) 2008 Elsevier B. V. All rights reserved.