The properties of germanium-tin alloys for infrared device applications

Germanium-tin alloys are attracting renewed interest for applications including the strain control of CMOS active channels in integrated circuits, and mid-infrared optical devices for medical imaging, chemical spectroscopy, and military counter-measures. With sufficient Sn content above about 10 %, there is the particularly interesting possibility of an energy bandgap that is direct in reciprocal space, which may lead to efficient light emitters and detectors.