GeSnOI technology for enhanced Si-based laser designs and performances

Direct band gap achievements in germanium by alloying with tin or by tensile strain engineering has enabled, in recent years, several demonstrations of laser emission in the 2-5µm wavelength range. This fast and promising emergence of CMOS-compatible laser technology in the Mid-IR faces, however, major issues, e.g. high threshold power densities, which limit the integration of GeSn as a gain media on a silicon chip for cost-efficient sensing and/or short-range Datacom devices. We show that combining tensile strain and Sn alloying enables one to effectively engineer the material band structure and its optical gain properties. We also evidence the importance of defects management on GeSn lasing characteristics, beyond the band-structure engineering. We discuss the potential of GeSnOI technology to address the above-mentionned aspects, which enabled to drastically reduce the lasing thresholds in microdisk laser cavities and reach continuous-wave operation in GeSn.