Low-frequency electrical properties of porous silicon

Silicon is the most commonly used semiconductor material for micro and nanodevices that can be build up on porous silicon. Such devices has a different response for different type of the molecule bounded to the surface of silicon, i.e. polar, positively or negatively charged molecules. As that others physical properties, e.g., luminescence properties, the surface of PS has an essential role in low-frequency (diffusional regime) electrical properties. Impedance spectroscopy results show that the behavior of the free pore surface is similar to EDL (Electrical Double Layer) of electrode-solvent interface; that is cannot by considered as perfectly polarized because the motion of electric charge is possible. But the surface of pore can be partially and selectively polarized. This paper brings information about the electrical behavior of the free surface of porous silicon. Results were obtained from processing the experimental components of the impedance measured in ac electric field on low frequency.