DETERMINATION OF ELECTROACTIVE SURFACE AREA OF NANO POROUS SILICON ELECTRODE BY CYCLIC VOLTAMMETRY

Abstract

Currently, nano-porous silicon (NP-Si) structures have been interestingly researched in many fields related to photo-electrochemical catalysis (PEC). Therefore, determination of electroactive surface area (ESA) for the NP-Si structures has an important role in determining approaches in material structures selection and its catalytic effects. In this work, the ESA of NP-Si electrode was determined by cyclic voltammetry (CV). The NP-Si electrode was fabricated by using an electrochemical-etching process of Si wafer (n-type) in HF acid solution. The NP-Si electrode was performed by cycling the potential in range of 0 ¸ 200 mV (vs Ag/AgCl reference potential) in H₂SO₄ solution (0.1 M) for the ESA determination under the principle based on surface capacitance characteristic of the NP-Si via a linear dependence of electric current on scanning rates of the CV curves. The nano-porous Si electrode was examined for surface state stability by immersion in H₂O₂ solution. The ESA value of the NP-Si electrode was determined to be approximate 150 cm² per a graphic surface area of 1 cm².