Design of an electrically pumped SiGeSn/GeSn/SiGeSn double-heterostructure midinfrared laser

This paper presents the conception, modeling, and simulation of a silicon-based group-IV semiconductor injection laser diode in which the GeSn-alloy active region has a direct band gap wavelength in the 1.8 to 3.0 μm midwave infrared for 6%–12% α-Sn. The strain-free monolithic P-type semiconductor/Intrinsic semiconductor/N-type semiconductor (PIN) bulk heterostructure, grown lattice matched upon a relaxed GeSn-buffer on silicon-on-insulator, is believed to be manufacturable in a complementary metal-oxide semiconductor fab. Detailed modeling is given for the type-I band offsets, carrier lifetimes, infrared gain profile and laser threshold current density Jth in a Fabry–Perot cavity having 20–100 cm−1 loss. The laser’s temperature of operation is determined by a combination of the radiative lifetime and the nonradiative lifetime due to unwanted Auger electron-hole recombination. If we keep Jth below 10 kA/cm2, then we find that this laser requires cooling in the 100–200 K range, whereas Jth at 300 K appears to be too high for a practical device. However, the GeSn quantum-well laser diode does offer a pathway to room-temperature operation.