Room Temperature Lasing in GeSn Microdisks Enabled by Strain Engineering

The success of GeSn alloys as active material for infrared lasers could pave the way toward a monolithic technology that can be manufactured within mainstream silicon photonics. Nonetheless, for operation on chip, lasing should occur at room temperature or beyond. Unfortunately, despite the intense research in recent years, many hurdles have yet to be overcome. An approach exploiting strain engineering to induce large tensile strain in micro-disk made of GeSn alloy with Sn content of 14 at% is presented here. This method enables robust multimode laser emission at room temperature. Furthermore, tensile strain enables proper valence band engineering; as a result, over a large range of operating temperatures, lower lasing thresholds are observed compared to high Sn content GeSn lasers operating at similar wavelength.

Automated summary

The success of GeSn alloys as active materials for infrared lasers has the potential to advance monolithic technology in mainstream silicon photonics. However, in order to operate on a chip, the lasers need to work at room temperature or higher. This study presents a strain engineering approach to induce large tensile strain in GeSn alloy micro-disks with a Sn content of 14 at%, enabling robust multimode laser emission at room temperature.