Germanium tin: silicon photonics toward the mid infrared

Germanium tin (GeSn) is a group IV semiconductor with a direct band-to-band transition below 0.8 eV. Nonequilibrium GeSn alloys up to 20% Sn content were realized with low temperature (160°C) molecular beam epitaxy. Photodetectors and light emitting diodes (LEDs) were realized from in situ doped pin