Nucleation and growth of selenium electrodeposition onto tin oxide electrode

The initial stages of selenium electrodeposition onto SnO2 coated glass substrates are studied using cyclic voltammetry and chronoamperometry. At low overpotential, the deposition of Se proceeds by a four-electron reduction of Se(IV) to Se(0) and a 2D growth under instantaneous nucleation followed by a multilayer spiral growth mode. At high overpotential, the deposition of Se occurs through a comproportionation reaction between Se(IV) and Se(-II) generated from a six-electron reduction of Se(IV), and a 3D growth under progressive nucleation.