Effect of the Electrode Geometry on the Diffusion-Current Problem of the Rotating Porous Silicon Electrode in HF Solution

The basic voltammetric data of silicon/ fluoride-electrolyte interfaces available in the literature appear to be rather divers because of the large number of experimental parameters like semiconductor type, crystallographic orientation, fluoride acid concentration CF, pH and electrode rotation rate. In the present work we have studied the effects of parameters such as electrode rotating rate upon the voltammograms in order to show the electrode geometry effects on current transport through Si/HF interface. The decrease of the current experimentally observed after the initial current peak (Si/HF current-potential curve) is investigated. The origin of this behaviour lies in substitution of Si-H surface bond by SiO2 in the first seconds following the potential jump. The diffusion current problem of a rotating porous silicon electrode has been analysed based on the mass transfer equations for partially blocked electrode. The blocking parameter is calculated.