Atomic force microscopy study of nanoporous gold surface and electrochemical properties

The morphology, surface oxide and strain evolution of nanoporous (np) gold were investigated using atomic force microscopy (AFM). Topographic AFM images show typical np structure with a few nanometers ligament size. Current sensing AFM results revealed semiconductor properties of the surface oxide, which may consist of Ag2O (p-type) and Ago (n-type). The surface oxide can effectively suppress the np structure coarsening. In-situ electrochemical AFM tests exhibit a refined macroscopic dimensional change of 40 nm within 0.35-0.7 V potential range. AFM can be used as an effective method to investigate the morphology and voltage-induced dimension changes in electrolyte. (C) 2019 Published by Elsevier Ltd on behalf of Acta Materialia Inc.