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Download fileReduced Lasing Thresholds in GeSn Microdisk Cavities with Defect Management of the Optically Active Region
journal contribution
posted on 16.09.2020, 11:45 authored by Anas Elbaz, Riazul Arefin, Emilie Sakat, Binbin Wang, Etienne Herth, Gilles Patriarche, Antonino Foti, Razvigor Ossikovski, Sebastien Sauvage, Xavier Checoury, Konstantinos Pantzas, Isabelle Sagnes, Jérémie Chrétien, Lara Casiez, Mathieu Bertrand, Vincent Calvo, Nicolas Pauc, Alexei Chelnokov, Philippe Boucaud, Frederic Boeuf, Vincent Reboud, Jean-Michel Hartmann, Moustafa El KurdiGeSn alloys are nowadays considered
as the most promising materials
to build Group IV laser sources on silicon (Si) in a full complementary
metal oxide semiconductor-compatible approach. Recent GeSn laser developments
rely on increasing the band structure directness by increasing the
Sn content in thick GeSn layers grown on germanium (Ge) virtual substrates
(VS) on Si. These lasers nonetheless suffer from a lack of defect
management and from high threshold densities. In this work, we examine
the lasing characteristics of GeSn alloys with Sn contents ranging
from 7% to 10.5%. The GeSn layers were patterned into suspended microdisk
cavities with different diameters in the 4–8 μm range.
We evidence a direct band gap in GeSn with 7% of Sn and lasing at
2–2.3 μm wavelength under optical injection with reproducible
lasing thresholds around 10 kW cm–2, lower by 1
order of magnitude as compared to the literature. These results were
obtained after the removal of the dense array of misfit dislocations
in the active region of the GeSn microdisk cavities. The results offer
new perspectives for future designs of GeSn-based laser sources.