CONICET | Buscador de Institutos y Recursos Humanos

The central purpose of this work is to combine semiconductor technology and surface functionalization in order to develop rationally designed porous silicon (PS) platforms based in the optical response of multilayer systems for sensitive and selective label-free detection. Optical porous silicon microcavities able to work as sensitive biosensors or chemical sensors were simulated and studied using computational codes. The results obtained from simulations were used to built specific microcavities .The structures were functionalized with 3-aminopropyl (triethoxy)silane (APTES). Porosities and thicknesses of single porous layers were determined by fitting their reflectance spectra. Once the growth rate of the porous layers as well as complex refractive indexes for different growing conditions were obtained, it was possible to develop a computational code to predict the reflectance spectrum for a PS multilayer with a given optical response. This code allows us to design and prepare optical microcavities having sharp resonances. Experiments with solvent vapours show that these structures have a large sensitivity as sensors. Two derivatization methods were studied with de objective to introduce aminosilane groups on the PS surface. One of them involves only a one step reaction, while the other involves two steps: a first oxidation with hydrogen peroxide, followed by the derivatization with APTES. Experimental results together with simulations show that the microcavity structures can be uniformly modified, allowing the incorporation of functional groups to bind specific receptors. The modification methods were tested showing that the two steps procedure is more reproducible than the single step one.