Cu2O nanocubes (edge length of 6 to 250 nm) have been produced by annealing a copper grid at 300 degrees C in air with the presence of tetraoctylammonium bromide (TOAB)-stabilized gold nanoparticles. The microstructure of the nanocubes has been investigated in details using conventional and high-resolution transmission electron microscopy (HRTEM), and chemical analysis has been performed using energy dispersive X-ray spectroscopy (EDS) and electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscopy (STEM). Based on the experimental results, a possible growth mechanism is proposed. (C) 2010 Elsevier B.V. All rights reserved.