We investigated the effect of the chemical properties of the interface on nonvolatile memory characteristics for small-molecule memory cells embedded with Ni nano-crystals surrounded by a NiO tunneling barrier. We used ultra-high voltage TEM, Auger, and XPS to characterize the physical and chemical properties of the interface. It was found that the occurrence of chemical reactions between the small-molecule layers and the surface of the NiO tunneling barrier surrounding the Ni nano-crystals (e.g., NiCO(3)) conclusively determine nonvolatile memory characteristics such as memory margin (I(on)/I(off) ratio), retention time, and endurance cycles of writing and erasing. (C) 2009 Elsevier B.V. All rights reserved.