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 electrodeposited into porous silicon (PS). Er doping was found to improve the room-temperature visible photoluminescence (PL) of PS, whereas Cu and Zn doping seemed to have a quenching effect. The current densities decreased exponentially with doping time in the entire electrodepositing processes of Er and Zn, which was true just in the beginning of Cu depositing. A phenomenological model based on the adsorption on the PS surface and the reduction of metal ions is proposed to explain the exponential dependence of the current density on doping time.