Photoluminescence of erbium–oxygen-codoped silicon multilayers prepared by molecular beam epitaxy

Erbium–oxygen-codoped silicon multilayer film, which consists of alternate erbium–oxygen-codoped silicon layers and oxygen-doped silicon layers, was synthesized by molecular beam epitaxy. Er3+-related luminescence from erbium–oxygen-codoped multilayer film is stronger than that of erbium–oxygen-codoped monolayer film and shows a weak temperature quenching behaviour. These improvements may be explained by the effect of O-doped Si layers in the multilayer film. The O-doped Si layers have a wide gap which prohibits the energy backtransfer effectively. At the same time, photogenerated carriers from silicon nanocrystals in O-doped Si layers could transfer the energy to neighboring Er3+ ions in Er–O-codoped Si layers by a tunneling process, thus enhancing the Er3+-related luminescence.