Effects of strain and nonparabolicity on optical gain and threshold current in Mid-Infrared InxGa1-xAsySb1-y/ Al0.35Ga0.65As0.03Sb0.97Quantum Well Lasers

We present an accurate kP model developed within the framework of the envelope function formalism to calculate the optical gain and the threshold current in type-I In_xGa_1-xAs_ySb_1-y/Al_0.35Ga_0.65As_0.03Sb_0.97 Quantum Well Laser Heterostructures and to optimize the laser emission near 3μm in such type-I systems with 0.40≤x≤0.60 and 0.10≤y≤0.25. Our calculations show that the combination of strain, band mixing, and anisotropy strongly affect conduction and valence bands states with important modification of fundamental electron and heavy holes effective masses. For structures emitting near 3μm, performance simulations display that room temperature laser emission could be expected. Indeed, anisotropy effects are found to induce in turn a decrease of the lasing threshold current densities with predicted values at around 1-3kA/cm² and an increase of the optical gain of the laser with a calculated modal gain value at around 50cm⁻¹ at room temperature (RT).