Surface Engineering

Porous Silcon Surface Chemistry

Current work focuses on functionalisation of pSi surfaces, primarily through hydrosilylation reactions of alkene species with the freshly etched, silicon hydride terminated pSi. The hydrosilylation reactions are performed using either thermal or UV light energy to initiate the conjugation of the alkene to the pSi surface. In the case of thermal hydrosilylations, a dense monolayer of the alkene species can be produced, covering the pSi surface and protecting it from degradation. By performing UV initiated hydrosilylations, the attachment of the alkene species to the surface can be patterned by using a photomask (figure 8). This allows patterned regions of specific surface chemistry to be produced within the pSi structure, which can be utilised for the attachment of desired species.

Alkene compounds can be synthesised to contain various chemistries that are accessible for further modification, such as amines, carboxylic acids and thiols. These reactive chemical species can be used to incorporate biomolecules and other small organic compounds of interest into the pores. Functionalised surfaces can then be used for a range of applications from tissue culture to drug delivery.

The techniques used to analyse the surface chemistry include infrared spectroscopy (IR), fluorescence microscopy, X-ray photoelectron spectroscopy (XPS) and contact angle.

 

Figure 8. Schematic of UV initiated patterned hydrosilylation of decyne on Si-H terminated pSi, and quenching of photoluminescence in patterned regions on pSi.

Figure 9. Quenching of photoluminescence in patterned regions on pSi.