Germanium Tin Light Emitters on Silicon

The energy and emission intensity of room temperature GeSn light emitting diodes based on Ge/GeSn/Ge pin heterostructures on Si substrates were investigated as function of Sn content for two series with different material properties. For good quality GeSn diodes an increase in emission intensity by a factor two compared to Ge diodes was measured and interpreted as proof of the reduction of the energy difference between indirect and direct bandgap. Compressive strain and nonradiative recombination were named as main obstacles for stronger emission intensities which are needed for electrically stimulated laser operation.