Solid-State Growth of One- and Two-Dimensional Silica Structures on Metal Surfaces

Crystalline or vitreous silica layers are new two-dimensional (2D) nanomaterials, which have shown surprising structural similarities with graphene and promise interesting properties. In this study, one-dimensional (1D) silica structures are formed on metal surfaces. In an in situ electron microscopy experiment it is demonstrated that lines of silica grow along step edges on metal surfaces. The growth of 1D silica occurs in competition with the formation of 2D networks and adopts the crystalline symmetry of the metal surface. Transformations between 1D and 2D structures are observed. Density functional theory calculations show that 1D silica is energetically favorable over 2D structures if surface steps prevail on the substrate. Our results indicate that lateral heterostructures with interesting properties may be developed on metal substrates.