Size and grain-boundary effects of a gold nanowire measured by conducting atomic force microscopy

Abstract

The resistivities of thin metal films and wires are highly sensitive to their polycrystalline structure and surface morphology because grain boundaries and surfaces provide additional scattering sites compared to bulk materials. Here, we investigated polycrystalline gold wires of nanometer-scale diameter that were—at some locations—connected through single grain boundaries. A detailed topography of the wires was recorded by atomic force microscopy. A Pt-coated tip in a conducting atomic force microscopy setup served as a mobile electrode to probe the resistance of a wire. Analyzing the topographical cross section and the resistance data allowed us to evaluate the effective specific resistivity of the wire as well as reflection coefficients of single grain boundaries.