Asymmetric strain-symmetrized Ge-Si interminiband laser

We present analysis of a proposed Si-based GeSi superlattice p-i-p laser diode grown on a relaxed Si-0.25 Ge-0.75 buffer layer. Local-in-k-space population inversion between HH2 injector and HH1 minibands at the superlattice minizone boundary is predicted at the 4.6-mu m lasing wavelength. The 2.94-nm Ge well width is three times the 0.98-nm Si barrier width so there is no net strain. A dipole element \z(21)\ = 5.7 Angstrom is calculated, leading to an expected gain of 238 cm(-1) at an injection current density of 3 kA/cm(2), Issues such as the waveguide design, critical thicknesses, doping levels, and expected threhold current density are addressed. Further optimization of the design is required.