A synchrotron radiation X-ray photoemission spectroscopy study of n -propyltriethoxysilane adsorption on Si(001)-2 × 1 at room temperature

The reaction of n-propyltriethoxysilane (PTES) with clean Si(001)-2 × 1 at room temperature is studied by synchrotron radiation X-ray photoemission spectroscopy (XPS). It is shown that PTES dissociatively adsorbs on the surface via the scission of at least two Si-O bonds. Adsorbate geometries are proposed accounting for the XPS data, and possible reaction paths are discussed, considering the zwitterionic nature of the surface silicon dimers. The understanding of the reactivity of the triethoxysilane termination on clean silicon paves the way to its possible use as an anchoring unit enabling the grafting of complex multifunctional molecules.