Synthesis of porous silicon through interfacial reactions and measurement of its electrochemical response using cyclic voltammetry

Porous silicon, an excellent material with fascinating physical and chemical properties, is usually formed by anodic polarization of single crystalline silicon in HF based solutions. Here, we show fabrication of porous silicon films ∼0.5-250 μm thick consisting of macropores and mesopores using a contactless electrochemical approach, where the silicon substrate is not under any external bias. Pore dimensions and porosity have been characterized by scanning electron microscopy (SEM) while subsequent cyclic voltammetry (CV) investigations delineate the underlying topographical differences between blanket and porous silicon surfaces. Our work not only offers a new scalable means of fabricating porous silicon structures but also questions the reliability of existing theories that depend on localized collection of electronic hole carriers through anodization of silicon for pore formation. We believe our results will open pathways for development of realistic models for porous silicon formation.