The Electrostatics of the Semiconductor-Electrolyte Interface
Authors: Petsev Dimiter N. , van Swol Frank , Fleharty Mark 
Published: February 2020

The semiconductor-electrolyte interface presents a great interest both form fundamental and applied perspective. Both phases have free mobile charges – ions in the electrolyte and electrons and/or holes in the semiconductor. Hence there will be distributions of charge density and potential in the electrolyte and in the semiconductor, which will be dependent on the interfacial charge as well as each other. This means that a perturbation of the charge or potential in one of the phases will elicit a response in the other one and vice versa. An important and interesting feature of the semiconductor-electrolyte interface is that the charge distribution may have to account for the fermionic nature of the charges present in the semiconductor. Exploring the high doped semiconductor limit allows us to also draw conclusion about the properties of metal-electrolyte interfaces.

Understanding the charge and potential interactions between that semiconductor and electrolyte has many practical implications. These include controlled assembly of semiconductor nanocolloids1, electronics and optoelectronics2-5, catalysis6, corrosion, sending and detection.7-11

Recently we have performed a theoretical analysis of the electrostatics of semiconductor-electrolyte interfaces.12-13 We have found that charge distributions in semiconductor and the electrolyte affect each other and this effect is particularly strong if the interfacial charge is accounted for by examining the surface chemistry. An illustration of this effect is shown in the Figure below which examined the interaction between two semiconductor nanocolloids suspended in electrolyte solution. We have found that the doping level of the particles has a strong effect on their stability against flocculation and coalescence. The effect of parameters such as electrolyte concentration, surface chemistry thermodynamics and doping levels were studied in details. The effect of the fermionic nature of the charge carriers in the semiconductor phase was also established.

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Figure 1