Modeling Infrared Superlattice Photodetectors: From Nonequilibrium Green’s Functions to Quantum-Corrected Drift Diffusion

Carrier transport in type-II superlattice photodetectors is investigated by means of a rigorous nonequilibrium Green’s function model based on a physics-based Büttiker-probe formalism. Intraband scattering self-energies (carrier-phonon interactions) are computed in the self-consistent Born approximation, while interband self-energies (Shockley-Read-Hall and optical transitions) are included in terms of semiclassical generation-recombination rates, neglecting interband renormalization effects. Current conservation is achieved with an efficient Newton-Raphson algorithm. While carrier transport in infrared detectors is usually understood in terms of quantities (e.g., mobilities and quasi-Fermi-levels) that are admittedly not germane to nonequilibrium Green’s function theory, the proposed model provides a quantum-kinetic description of tunneling, miniband transport, hopping, and carrier extraction within a drift-diffusion-friendly framework. The connection with semiclassical theories allows exploration of the possibilities offered by Poisson-Schrödinger or localization landscape drift-diffusion approaches.