Research into creation of optoelectronic devices (known as silicon-based photonics) reveals that the technology would be compatible with electronic integrated circuit and microelectromechanical sensors/systems (MEMS) technologies. Silicon-based photonics could enable development of advanced multifunctional chips where electronics, optics, and MEMS could be effectively combined. Light emitters (LEDs and lasers) have been the most challenging components to obtain in the family of photonic devices because bulk crystalline silicon is an indirect bandgap material. In silicon, radiative processes may be insignificant, and research indicates that recombination takes place through impurities or defects. The radiative process is very fast, and, in a good quality crystal, defect or impurity-assisted non-radiative processes cannot compete with it. This indicates a conversion efficiency that is 'close to unity for a material such as GaAs. Because of the very low radiative rate in bulk silicon, very high carrier concentrations are required to get a population inversion. Research into such approaches as use of erbium in silicon and quantum confinement has been conducted. A viable technique for creation of quantum confinement is production of nanocrystals in a silica matrix. Challenges to be addressed before lasing can be expected are described. Optically pumped silicon lasers have been demonstrated via the Raman effect, and the next milestone will be an electrically pumped laser.