Computational design of metamorphic In(N)AsSb mid-infrared light-emitting diodes

We present a theoretical investigation of the optical properties of metamorphic $\mathbf{InN}_{\pmb{y}}(\mathbf{As}_{1-\pmb{x}}\mathbf{Sb}_{x})_{1-\pmb{y}}/\mathbf{Al}_{z}\mathbf{In}_{1-\pmb{z}}$ As type-I quantum wells (QWs) designed to emit at mid-infrared wavelengths. The use of $\mathbf{Al}_{z}\mathbf{In}_{1-z}$ As metamorphic buffer layers has recently been demonstrated to enable growth of lattice-mismatched In. $\mathbf{As}_{1-\pmb{x}}\mathbf{Sb}_{\pmb{x}}$ QWs having emission wavelengths $\underset{\sim}{>}$ 3 $\mu \mathbf{m}$ on GaAs substrates. However, little information is available regarding the properties of this newly established platform. We undertake a theoretical analysis and optimisation of the properties and performance of strain-balanced structures designed to emit at 3.3 and $4.2\ \mu \mathbf{m}$, where we recommend the incorporation of dilute concentrations of nitrogen (N) to achieve emission beyond $4\ \mu \mathbf{m}$. We quantify the calculated trends in the optical properties, as well as the ability to engineer and optimise the overall QW performance. Our results highlight the potential of metamorphic $\mathbf{InN}_{y}(\mathbf{As}_{1-x}\mathbf{Sb}_{x})_{1-y}/\mathbf{Al}_{z}\mathbf{In}_{1-z}$ As QWs for the development of mid-infrared light-emitting diodes, and provide guidelines for the growth of optimised structures.