AbstractEfficient room temperature silicon based light emitting diodes have been fabricated by conventional ULSI processes using a recently developed dislocation engineering approach. Strong silicon band edge luminescence was observed from devices fabricated by low energy boron implantation into silicon substrates followed by high temperature rapid thermal annealing. In this paper we review the luminescence properties of silicon light emitting diodes and give an example of how this approach can be employed to fabricate and optimise light emitting devices operating at different wavelengths.