GeSn/SiGeSn photonic devices for mid-infrared applications: Experiments and calculations

In this work, a fully strained GeSn photodetector with Sn atom percent of 8% is fabricated on Ge buffer on Si(001) substrate. The wavelength lambda of light signals with obvious optical response for Ge0.92Sn0.08 photodetector is extended to 2 mu m. The impacts of compressive strain introduced during the epitaxial growth of GeSn on Ge/Si are studied by simulation. Besides, the tensile strain engineering of GeSn photonic devices is also investigated. Lattice-matched GeSn/SiGeSn double heterostructure light emitting diodes (LEDs) with Si3N4 tensile liner stressor are designed to promote the further mid-infrared applications of GeSn photonic devices. With the releasing of the residual stress in Si3N4 liner, a large biaxial tensile strain is induced in GeSn active layer. Under biaxial tensile strain, the spontaneous emission rate r(sp) and internal quantum efficiency eta(IQE) for GeSn/SiGeSn LED are significantly improved.