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 °C 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 H 2 SO 4 ) 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 CCl 4 and water, and against corrosion when exposed to 100% humidity in air.