Energy band diagrams for the photo-electrochemical dissolution of n-Si(1 0 0) in HF

A technique in combination of theoretical and experimental methods was used to establish the energy band diagrams for the photo-electrochemical dissolution of n-Si(1 0 0) in various HF solutions. Based on theoretical calculation in the band gap of silicon and experimental measurements in both open circuit potential (OCP) and flatband voltage (Vfb) of the n-Si/HF, we successfully established the energy band diagrams, and estimated the activation energy (Eact) for the photo-electrochemical reaction of the system. The Eact data were advantageous to elucidate the reaction kinetics. The dissolution rate of silicon increased to a maximum with increasing the HF concentration from 0.5 to 2.0 M; it decreased with further increasing in HF concentrations. This concentration effect could be interpreted in terms of energy band diagrams and the Eact data.