Charge Transport in Interband Cascade Lasers: An Ab-Initio Self-Consistent Model

Interband cascade lasers (ICLs) stand out due to their low threshold current and minimal power consumption, rendering them viable sources for compact and mobile devices in the mid-infrared. Since their first demonstration, they experienced major performance improvements. Many of them originate, on one hand, from technological enhancements and, on the other hand, also from restricted numerical analysis. Encouraged by the impact of restricted models, an ICL-specific simulation tool can lead to performance breakthroughs and a better comprehension of governing mechanisms. Drawing from an evaluation of existing tools designed for quantum cascade structures, we implemented a self-consistent density matrix rate equation model generalized to simulate the transport in both conduction and valence band heterostructures. Albeit the extensive inclusion of the quantum effects, special care was taken to maintain a high numerical efficiency. Our charge transport model additionally considers optical field calculations, allowing for predictive calculations of light-current-voltage (LIV) curves. We benchmark the model against well-established ICL designs and demonstrate reliable performance predictability. Additionally, we give detailed insights into device characteristics extracted from our model. This ultimately allows us to deepen our understanding of ICLs and define existing and generate novel designs.