The initial stages of selenium electrodeposition onto SnO(2) 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(W) 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(]V) and Se(-II) generated from a six-electron reduction of Se(IV), and a 3D growth under progressive nucleation. (C) 2009 Elsevier B.V. All rights reserved.