Sulfide passivation of III–V semiconductors: Kinetics of the photoelectrochemical reaction*

A phenomenological model is proposed to describe sulfide passivation of the surfaces of III–V semiconductors as a process of charge transfer between a semiconductor and a passivation solution. The model assumes that formation of the passivation sulfide coat occurs as a result of oxidation of the semiconductor in a photoelectrochemical reaction. The growth rate of the passivating coat is determined by the rate at which electrons are transferred from the semiconductor into the solution, as well as by the energy which binds atoms in the surface layer of the semiconductor and the heat evolving in the process. It is found that the growth rate of the coat is dependent upon conductivity type and doping level of the semiconductor, hydrogen ion exponent, and concentration of the solution and, as well, the intensity of light incident upon the electrolyte/semiconductor interface. In terms of the model, passivation of different III–V semiconductors is considered.