Prof. Asscher


Research Projects









Laser patterning and lithography Collision induced processes Clusters characterization and catalysis Oxide nano clusters characterization Photo-catalysis of caged molecules Reactivity of porous silica


Reactivity of porous silica


Porous Silicon is a material composed of submicron to nanometer scale pores surrounded by nanometer size Si crystallites. The Porous Silicon (PS) samples are prepared by electrochemical etching in solutions of Hydrofluoric acid, and they exhibit luminescence initiated by either light absorption (Photo Luminescence) or initiated by an electronic field (Electro Luminescence).

We have developed the capability to prepare porous Silicon samples and are studying chemical reactivity within the Silicon pores under UHV conditions. Here, one takes advantage of the enormous surface area of a PS sample (~500 m2cm-3), that considerably enhances the effect of any chemical process occurring on the surface, e.g. adsorption and desorption of gas molecules and oxidation.

The PS reactivity is being studied as a function of pore dimensions, density and level of porosity, which can be determined by the initial etching parameters.