Considerations for interpretation of luminescence from silicon-on-insulator light emitting structures

Silicon-based, light emitting diodes (LEDs) and light emitting structures without electrical contacts have been integrated on silicon-on-insulator (SOI) wafers. The room temperature characterization of these samples using electro- and photo-luminescence is described. All samples emit at 1150 nm near the band-edge of Si, and samples that receive Er implantation emit additionally at a band centered at 1550 nm. Photoluminescence from the SOI wafers shows a strong influence from the optical cavity created by the Si/SiO2 structure. This effect is corrected using a classical plane-wave model. The importance of this procedure is highlighted for the rigorous interpretation of the luminescent spectrum from any SOI system. The external quantum efficiency of the LEDs is measured to be 8.7 × 10−6. The potential impact on this efficiency resulting from the structure of diodes fabricated on SOI rather than bulk silicon is discussed.