Photoluminescence of erbium, zinc and copper doped porous silicon and a phenomenological model for the metal electrodeposition

High concentrations of metals Er, Cu and Zn, were potentiostatically electr odeposited into porous silicon (PS). Er doping was found to improve the roo m-temperature visible photoluminescence (PL) of PS, whereas Cu and Zn dopin g seemed to have a quenching effect. The current densities decreased expone ntially with doping time in the entire electrodepositing processes of Er an d Zn, which was true just in the beginning of Cu depositing. A phenomenolog ical model based on the adsorption on the PS surface and the reduction of m etal ions is proposed to explain the exponential dependence of the current density on doping time.