Low-Temperature Growth of Amorphous Water Ice on Ag(111)

Abstract

Although the wetting of hydrophilic surfaces on the macroscale is a well-known phenomenon, we here develop a microscopic understanding of the more recently discovered complete covering of hydrophobic surfaces by a uniform water layer. For this aim, we deposit D2O on Ag(111) at two different temperatures, 20 and 96 K, and investigate the geometry of the layers at coverages up to four bilayers (BL) by low-temperature scanning tunneling microscopy. In the coverage range up to 0.5 BL, the ice grows in the form of islands that differ largely in size, shape, and density, but surprisingly not in their height. Moreover, the water fills the layer with islands of the same thickness of three to four bilayers at both temperatures. The different island shapes and densities in the coverage range before coalescence are attributed to details in the interaction between water nanoclusters and activated cluster diffusion at the higher growth temperature of 96 K, as visualized in time-lapsed series of scanning tunneling micr...