Atomic Structure of a Thin Silica Film on a Mo(112) Substrate: A Two-Dimensional Network ofSiO4Tetrahedra

Abstract

The structure of a thin single crystalline SiO(2) film grown on Mo(112) has been studied by scanning tunneling microscopy, infrared reflection absorption spectroscopy, and x-ray photoelectron spectroscopy. In excellent agreement with the experimental results, density functional theory calculations show that the film consists of a two-dimensional network of corner sharing [SiO(4)] tetrahedra, with one oxygen of each tetrahedron binding to the protruding Mo atoms of the Mo(112) surface.

On the geometrical and electronic structure of an ultra-thin crystalline silica film grown on Mo(112)

“…Furthermore, at certain tunneling parameters the Si atoms could be imaged (Fig 2b) and, again, this fact has been proven by comparing the experimental and simulated STM images [32,36]. [36] showed that isolated [SiO 4 ] clusters must appear in STM as large single spots (see Fig.…”

“…Further XPS studies have verified formation of two different O species in the "Opoor" silica films [32,36]. Two overlapping signals centered at ~532.5 and ~531.…”

“…1c). (Note, that this structure was suggested but rejected by was further corroborated by density functional theory (DFT) calculations [32,36].…”

“…However, Chen et al [28], analyzing high resolution electron energy loss spectra The interest in the structure of ultra-thin films was reinforced after Weissenrieder et al [32], modifying the preparation procedure, reported a scanning tunneling microscopy (STM) study of the silica films with atomic resolution. The STM images revealed a honeycomb-like surface on the extended flat terraces separated by the monoatomic steps of the Mo substrate underneath (Fig.…”

Realization of an atomic sieve: Silica on Mo(112)

“…4,5 The system consists of an ultra-thin silicon-dioxide film that is prepared on a Mo(112) surface. 6,7,8 The fundamental building blocks of the oxide layer are six-membered -Si-O-rings, enclosing a hole of 3-4 Å diameter. These openings provide access to nano-pores located at the Mo-silica interface, which offer an attractive binding environment for metal atoms and small molecules.…”