In situ observation of Cu electrodeposition and dissolution on Au(100) by high- speed atomic force microscopy

The initial stages of Cu electrodeposition and dissolution on an Au(100) electrode in sulfuric acid solution were studied by high-speed atomic force microscopy. Dynamic observations revealed that Cu islands formed on the Au terraces within a few seconds. The islands grew to approximately 100 nm as two thick layers overlapped. The AFM height profile results indicated that each layer consisted of 3-8 atomic layers. Dissolution occurred when an anodic potential was applied, with the bottom layer dissolved preferentially. Correlation of these observations with electrochemical data from cyclic voltammetry indicated differences in the rates of deposition and dissolution.