Electroluminescence and excitation mechanism of erbium ions in erbium-doped crystalline silicon

Electroluminescence (EL) of photodiodes fabricated from erbium-implanted silicon is studied at direct bias of p-n junction. A correlation between the intensities of EL of free excitons and erbium ions is found in dependence on pumping current. A model of f-shell excitation of optically active erbium ions is proposed basing on the assumption that the excitation of erbium ions occurs via capture of free excitons on neutral donor formed by erbium-oxygen complex with a subsequent auger-excitation of f-shell of erbium ion during recombination of a bound exciton. The model proposed permits us to described the experimental results.