Optimisation of Nanostructured Porous Silicon Surface Chemistry Towards Biophotonic Sensors

Narrow line-width porous silicon rugate filters, fabricated by electrochemical etching of crystalline silicon with sinusoidal variation in the current density, provide a class of optical material that may find utility in biosensing applications. Herein, we demonstrate the use of hydrosilylation chemistry to passivate the filters from oxidation, and to provide coupling points for attachment of biorecognition species. Porous silicon rugate filters were derivatised with two functional alkenes and were characterized using Fourier transform infrared spectroscopy (FTIR) concurrently with analysis of the reflectivity spectrum throughout organic derivatisation. The reproducible optical signals upon chemical and biological modification may provide a robust methodology for sensing of biological species and open the way for a new class of optical biosensor