Facet-Dependent Electrical Conductivity Properties of Silver Oxide Crystals

Ag2O cubes, truncated octahedra, rhombic dodecahedra, and rhombicuboctahedra were synthesized in aqueous solution. Two tungsten probes were brought into contact with a single particle for electrical conductivity measurements. Strongly facet-dependent electrical conductivity behaviors have been observed. The {111} faces are most conductive. The {100} faces are moderately conductive. The {110} faces are nearly non-conductive. When electrodes contacted two different facets of a rhombicuboctahedron, asymmetrical I-V curves were obtained. The {111} and {110} combination gives the best I-V curve expected for a p-n junction with current flowing in one direction through the crystal but not in the opposite direction. Density of states (DOS) plots for varying number of different lattice planes of Ag2O match with the experimental results, suggesting that the {111} faces are most electrically conductive. The thicknesses of the thin surface layer responsible for the facet-dependent properties of Ag2O crystals have been determined.