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Two‐dimensional oxide films are potentially useful for future technological applications, but also important objects to study model catalyst systems on the more fundamental side. Here we study silica, germania, and mixed silica‐germania films supported on a metal single crystal surface Ru(0001). Those mixed films are interesting objects to systematically modify the properties of silica films, which may be used as membranes or covers for model studies in confined space, due to the modification of the rather stiff silica layers by incorporating germanium atoms replacing silicon atoms. Here we report a combined experimental and theoretical study of such layers, where we show how X‐ray photoelectron spectroscopy in combination with LEED and I/V LEEM measurements allow us to judge the formation of such mixed films. [ABSTRACT FROM AUTHOR]

The present review reports on the preparation and atomic‐scale characterization of the thinnest possible films of the glass‐forming materials silica and germania. To this end state‐of‐the‐art surface science techniques, in particular scanning probe microscopy, and density functional theory calculations have been employed. The investigated films range from monolayer to bilayer coverage where both, the crystalline and the amorphous films, contain characteristic XO4 (X=Si,Ge) building blocks. A side‐by‐side comparison of silica and germania monolayer, zigzag phase and bilayer films supported on Mo(112), Ru(0001), Pt(111), and Au(111) leads to a more general comprehension of the network structure of glass former materials. This allows us to understand the crucial role of the metal support for the pathway from crystalline to amorphous ultrathin film growth. [ABSTRACT FROM AUTHOR]

A new two‐dimensional (2D) germanium dioxide film has been prepared. The film consists of interconnected germania tetrahedral units forming a bilayer structure, weakly coupled to the supporting Pt(111) metal‐substrate. Density functional theory calculations predict a stable structure of 558‐membered rings for germania films, while for silica films 6‐membered rings are preferred. By varying the preparation conditions the degree of order in the germania films is tuned. Crystalline, intermediate ordered and purely amorphous film structures are resolved by analysing scanning tunnelling microscopy images. [ABSTRACT FROM AUTHOR]

Keywords: amorphous structures; crystalline materials; germania; metal-supported films; silica EN amorphous structures crystalline materials germania metal-supported films silica 1 1 1 01/29/21 20210126 NES 210126 B The thinnest possible films b of the glass-forming materials silica and germania were so far investigatd by employing scanning probe microscopy and density functional theory calculations. A more general comprehension of the network structure of glass former materials allows to understand the crucial role of the metal support for the pathway from crystalline to amorphous ultrathin film growth. Amorphous structures, crystalline materials, germania, metal-supported films, silica. [Extracted from the article]