Nonequilibrium Green’s function study of phonon-dressed Auger transitions in superlattice infrared photodetectors

Antimonide-based type-II superlattices represent a promising alternative to mercury cadmium telluride in infrared imaging applications. Among the original motivations for the development of type-II superlattices as a material system for infrared photodetectors is Auger engineering, the possibility of tailoring Auger processes to increase the "intrinsic"minority carrier lifetime at long wavelengths. We investigate Auger transitions in antimonide-based superlattices by means of a nonequilibrium Green's function model based on a multiband description of the electronic structure and a GW treatment of carrier-carrier interactions. As carrier-phonon interactions mediated by acoustic deformation potential and polar optical scattering are included by means of appropriate self-energies, the resulting GW Auger rates may be considered as "phonon-dressed."The spatial and spectral resolution afforded by the model provides a clear, graphical representation of the transitions contributing to the recombination process. A detailed study of Auger transitions in conventional and polytype superlattice absorbers demonstrates the effectiveness of the proposed approach for the design of Auger-suppressed infrared photodetectors. The calculated Auger coefficients are in good agreement with measurements extracted from pulsed threshold current densities of midwave infrared lasers with active regions realized with type-II quantum wells.