Surface-modified CuO layer in size-stabilized single-phase Cu2O nanoparticles

Activated reactive evaporation has been used to grow copper oxide nanoparti cles in the size range of 8-100 nm. X-ray diffraction spectra clearly show the presence of a single Cu2O phase. Detailed x-ray photoelectron spectrosc opy studies show an increase in the ionicity of the Cu2O system with decrea sing particle size. Depth profiling and finger printing of x-ray photoelect ron spectra reveal that the Cu2O nanoparticles are capped with a CuO surfac e layer of thickness approximate to1.6 nm. This study strongly suggests tha t the stabilization of the cubic Cu2O nanophase is enhanced by the formatio n of a CuO surface layer. (C) 2001 American Institute of Physics.