AN INVESTIGATION OF THE IMAGE POTENTIAL AT THE SEMICONDUCTOR ELECTROLYTE INTERFACE EMPLOYING NONLOCAL ELECTROSTATICS

Using recent developments of solid state and surface physics, the image potential (IP) energy is calculated for a test charge situated in an electrolyte near the surface of a doped semiconductor electrode. The effect of the structure of the semiconductor and solvent on the electrostatics is addressed through the static dielectric function ε{lunate}(q). Specifically discussed in light of the results are implications for ion adsorption to the electrode and reorganization energy. At lower ionic strengths (1:1 electrolytes at a maximum of 0.1 M were considered) the IP is found to be a rather sensitive function of the ε{lunate}(q) of both the solvent and SC, and a wide variety of behavior is displayed. In opposition to simplistic classical treatments, image potentials corresponding to repulsion of the charge from the electrode are sometimes found even for highly doped semiconductors. At higher ionic strengths the image potential behavior is predominantly repulsive. The approach shows a host of concerns that have hitherto received little or no consideration for the semiconductor electrode/electrolyte interface. Treatments of the image potential energy for the metal electrode/electrolyte interface have appeared previously and comparisons to this interface are made. © 1990.