Prospects of efficient band-to-band emission in silicon LEDs

This paper presents a review of light emission from forward-biased diodes in silicon. After a treatment of the carrier recombination physics in this indirect-bandgap material, the article describes important works in this field. Then, routes are proposed for further improvement of the internal quantum efficiency for light emission. Properly setting the carrier injection level limits the impact of both Shockley-Read-Hall recombination and Auger recombination. However, the geometrical design of the diode has a strong influence on the overall quantum efficiency. In this design, one must deal with surface recombination at semiconductor-insulator interfaces as well as contact recombination. New attributes of advanced CMOS generations, such as embedded SiGe, offer additional opportunities for silicon light-emitting diode architectures and their application.