Strong efficiency improvement of SOI-LEDs through carrier confinement

Contemporary silicon light-emitting diodes in silicon-on-insulator (SOI) technology suffer from poor efficiency compared to their bulk-silicon counterparts. In this letter, we present a new device structure where the carrier injection takes place through silicon slabs of only a few nanometer thick. Its external quantum efficiency of 1.4 • 10−4 at room temperature, with a spectrum peaking at 1130 nm, is almost two orders higher than reported thus far on SOI. The structure diminishes the dominant role of nonradiative recombination at the n+ and p+contacts, by confining the injected carriers in an SOI peninsula. With this approach, a compact infrared light source can be fabricated using standard semiconductor processing steps.