Germanium-tin is an alloy of the elements germanium and tin, both located in group 14 of the periodic table.
Despite this limitation, it has useful properties for band gap and strain engineering of silicon-integrated optoelectronic and microelectronic semiconductor devices.
[1][2] Therefore, low temperature molecular beam epitaxy or chemical vapor deposition techniques are typically used for their synthesis.
[3][4] At a Sn content beyond approximately 9%, germanium-tin alloys become direct gap semiconductors having efficient light emission suitable for the fabrication of lasers.
This is still an active research area, but germanium-tin lasers operating at low temperatures have already been demonstrated.