Molecular Monolayers on Silicon Surfaces

Controlled formation of organic molecular monolayers on silicon surfaces offers the promise of enhancing the functionality of existing and emerging silicon based materials and devices. The synthetic tunability and diversity of properties of organic molecules suggests a range of promising applications for the resulting hybrid organic/silicon structures. At the simplest level, molecular monolayers can serve to passivate the surface, protecting the underlying substrate or structure from unwanted reactions or processes which degrade its properties. However, these monolayers can be much more than passive protective coatings, controllably altering the properties and imparting new functionality to bulk or nanostructured materials. Formation of monolayers with a variety of terminal functional groups can be used, for example, to tailor the wettability of the surface or modulate the electronic properties of the substrate through longrange field effects. Immobilization of biomolecules or other types of selective receptors on the surface offers opportunities for the development of novel sensing platforms based on electrical, optical or mechanical transduction of chemical binding events. Attachment of redox active or other types of “molecular switch” molecules (e.g., photochromic or electrochomic molecules) to silicon could enable fabrication of molecular scale memory or logic elements integrated with conventional silicon based microelectronic devices.