2D hexagonal photonic crystal GeSn laser with 16% Sn content

We demonstrate lasing in an optically pumped GeSn photonic crystal membrane with 16% of Sn. A guided band-edge mode lased up to 60 K. A good agreement was found between experimental and calculated reduced mode frequencies of the photonic crystal. The active Ge_0.84Sn_0.16 layer was grown on a step-graded GeSn buffer, limiting thereby the density of misfit dislocations. The thresholds obtained (227 kW/cm² at 15 K to 340 kW/cm² at 60 K) were comparable to our previous works on suspended microdisks, highlighting the robustness of the GeSn optical gain against potential surface recombination effects stemming from a high surface-to-volume ratio.