Water after-etching of n-type porous silicon in an electric field

Water after-etching of porous silicon in an external electric field is studied. The application of the electric field, irrespective of its strength and orientation, is shown to decrease the etch rate. When the field vector is directed from the porous layer inward to the sample, the electrode potential in the silicon-electrolyte system sharply changes; for E>6 kV/cm, the changes become periodic. Experimental data suggest the presence of a circulating current in the single-crystal silicon-electrolyte-quantum wire system.