Stability enhancement of partially-oxidized porous silicon nanostructures modified with ethyl undecylenate

The thermal reaction of ethyl undecylenate with a hydrogen-terminated porous silicon surface takes place at 85 degreesC to yield an organic monolayer covalently attached to the surface through Si-C bonds. The presence of traces of water in ethyl undecylenate induces a partial oxidation of the surface and leads to a surface that is composed of alkylated and oxidized regions. A PSi surface with a comparable chemical composition was prepared by the direct reaction of an electrochemically anodized PSi surface (in 1 M H2SO4) with anhydrous ethyl undecylenate. The physical and chemical properties of the functionalized surfaces have been characterized using photoluminescence, transmission infrared, and X-ray photoelectron spectroscopies. The derivatized surfaces proved to be very stable in boiling CCl4 and water, and against corrosion when exposed to 100% humidity in air.