Is there a future for semiconducting silicides? ( invited)

Silicon is commercially by far the most important semiconductor, however, because silicon has an indirect band gap it would initially appear to be unsuitable for optoelectronic applications. A major research challenge is, therefore, to achieve high intensity light emission from silicon and to engineer active and passive optical structures within it. This paper examines the potential of semiconducting silicides (principally, βFeSi 2 and Ru 2Si 3) for silicon-based optoelectronic applications. It traces the history of the subject from the first photoluminescence spectrum from βFeSi 2 to a working LED which uses βFeSi 2 precipitates as a route for fast radiative recombination. Recent results on semiconducting Ru 2Si 3 are also reported, which show, for the first time, that this material can be fabricated by high dose ion implantation. They also reveal a direct band gap of 0.91 eV. The future for semiconducting silicides is examined and, although there are still barriers to overcome — the future looks bright.