Light emission in silicon nanostructures

The many and diverse approaches to materials science problems have greatly enhanced our ability in recent times to engineer the physical properties of semiconductors. Silicon, of all semiconductors, underpins nearly all microelectronics today and will continue to do so for some time to come. However, in optoelectronics and, more recently, in photonics, the severe disadvantage of an indirect band gap has limited the application of elemental silicon. Here we review a number of diverse approaches to engineering efficient light emission in silicon nanostructures. These different approaches are placed in context and their prospects are assessed for applications in silicon-based photonics.