Microstructure evolution of Cu atomic islands on liquid surfaces in the ambient atmosphere

We report the microstructure evolution of copper(Cu) nm-sized atomic islands on silicone oil surfaces in the ambient atmosphere. The origin of these nearly free sustaining atomic islands is explained by a three-stage growth model. The first stage is the nucleation and growth of atomic granules. Subsequently, the compact atomic islands grow by the aggregation of the atomic granules. Finally, they adhere to each other and form branched atomic islands. During the characteristic evolution, the atomic granules reconstruct and the average height of the atomic islands increases from 7.0±1.0 nm to13.0±1.0 nm. The detailed evolution mechanism of the Cu atomic islands is presented.