Confinement induced enhancement of the emission in Er-implanted Si/SiO2 quantum wells fabricated on SOI substrates

Single Si/SiO2 quantum wells were fabricated using silicon on insulator (SOI) substrates, the upper barrier being a thin thermally oxidized Si layer. Samples were Er and O implanted at low energy in order to center their concentration profile in the well, and then annealed. A bulk Si sample implanted under the identical conditions was used as a reference. We present low temperature photoluminescence results using UV excitation in order to create photogenerated carriers mainly in the Si well. We show that the 1.54-μm photoluminescence is much more intense for Er in a well than for Er in implanted bulk silicon. We show that infrared emission occurs through an energy transfer mechanism from Si to Er centers. Confinement prevents the escape of photogenerated carriers towards the substrate and promotes energy transfer towards optical active erbium center.